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A used-car buying budget begins with the amount required to complete the transaction, not the listing price or a monthly payment alone. Tax, title and registration, inspection, optional products and delivery can move the cash requirement. Selling the existing car adds another calculation because its sale price and the owner’s usable proceeds are different amounts when a loan remains.
The worksheet below uses Texas’s published tax rate, one inspection provider’s price and one lender’s minimum used-auto APR checked in October 2026. Car prices, the fee allowance and the sale/payoff example are assumptions. They show the accounting without claiming a national purchase average, a promised loan or an individual tax result.
Key figures
- 6.25% Texas motor vehicle sales tax
- $220 Lemon Squad standard pre-purchase inspection
- $21,570 Example: car purchase and checks combined
The out-the-door offer establishes the purchase subtotal
Ask for an itemized offer identifying the VIN, vehicle price, tax, government charges, dealer charges and optional products. An advertised price excluding required fees is not the final amount to compare with another seller. A quote including an optional warranty is also a different package from a bare purchase.
The dealer fee guide explains the distinction between fees and products. Confirm whether a cash price, dealer-financed incentive or delivery arrangement changes the offer. Save the itemized version used in the comparison so a later payment worksheet can be reconciled with it.
Count trade-in credit and a cash down payment separately from the vehicle’s selling price. They change how the purchase is funded, and a qualifying trade can change the taxable base in some states. They do not mean the seller reduced the price of the replacement car by the same amount.
Taxes and checking costs turn a listing into a budget
Texas’s published motor vehicle sales-tax rate is 6.25% of the sales price after the trade-in allowance, with separate standard presumptive value provisions for private-party used vehicles. Applying the rate to a hypothetical $20,000 taxable dealer purchase without a trade gives $1,250. The state example should not be transferred to another jurisdiction or used to bypass its valuation rules.
Lemon Squad publishes a $220 standard inspection for cars newer than 20 years and a $330 classic inspection for cars 20 years or older. Its optional CARFAX add-on is $34.99. A seller-provided current report might avoid that duplicate purchase, but verify the VIN, date and report scope.
| Hypothetical purchase worksheet | Amount | Basis |
|---|---|---|
| Vehicle price | $20,000 | Assumed offer |
| Illustrative sales tax | $1,250 | 6.25% of assumed taxable price |
| Title, registration and other fee allowance | $100 | Placeholder, replace with itemized charges |
| Standard inspection | $220 | Named provider’s published price |
| Cash purchase and checking subtotal | $21,570 | Arithmetic, excluding other expenses |
Source note: Texas Comptroller for the stated tax rate and trade-in treatment; Lemon Squad for inspection pricing. Vehicle price and $100 fee allowance are assumptions, not state fee quotes. Taxable value and eligibility require verification.
- Sales tax$1,250
- Fee allowance$100
- Pre-purchase inspection$220
Source note: Texas Comptroller for the stated tax rate and trade-in treatment; Lemon Squad for inspection pricing. Vehicle price and $100 fee allowance are assumptions, not state fee quotes. Taxable value and eligibility require verification.
The placeholder is deliberately visible: title and registration cannot be established by copying a round number into every budget. Replace it with the destination state’s fees and the actual vehicle requirements. If a private-party taxable value exceeds the agreed price under the state’s rule, revise the tax calculation as well.
Inspection spending comes before the repair allowance
An inspection price pays for a defined assessment, not all repairs discovered during it. Obtain findings for the offered vehicle and price any recommended work separately. A car requiring tires and overdue scheduled service cannot be treated as identical to a matched car with that work recently documented.
The pre-purchase inspection guide addresses access and scope. If the seller will not permit the assessment, record the unresolved condition rather than estimating that a small repair allowance must cover it. Report purchases and travel spent on a car ultimately declined are checking expenses, not deposits that require completing the sale.
Keep first-month insurance, known maintenance and delivery outside the purchase-price subtotal until quotes are available. These costs affect money needed to put the car into use. A monthly loan estimate that ignores them can understate the early cash required even when the installment fits the budget.
Financing converts the principal into a larger repayment total
Navy Federal’s October 8, 2026 schedule advertises used-auto APRs as low as 4.79% for 12–36 months and 5.29% for 37–60 months. Membership and underwriting apply. The offer for a buyer and VIN can be higher or unavailable; the advertised minimum is a calculation input, not an approval.
With a hypothetical $20,000 fixed-rate loan for 60 months at 5.29%, equal monthly installments are about $380.09 and scheduled payments total $22,805.26. Interest is $2,805.26. This assumes no additional loan fees and uses APR divided by 12 as the monthly rate, with totals calculated before rounding each payment.
If the worksheet’s $1,570 tax, fee allowance and inspection are paid upfront while only $20,000 is borrowed, total purchase and scheduled financing spending becomes $24,375.26. It would be wrong to add the borrowed $20,000 again to the scheduled payment total; repayment already includes principal.
The cash versus financing comparison shows other terms. If all costs are financed instead, calculate the loan using the new principal and any changed rate. An upfront down payment is not a finance charge, and an optional financed product should remain identifiable in the amount borrowed.
Sale proceeds and a trade-in need their own worksheet
If a hypothetical existing car sells for $12,000 and its lender payoff is $7,000, the owner has $5,000 before selling expenses. Use a dated payoff rather than the balance on an old statement because accrued interest or other amounts can change settlement. A $12,000 sale does not supply a $12,000 down payment while the lien still requires payment.
For a qualifying $12,000 trade-in against a Texas dealer purchase, the 6.25% rate can produce a $750 tax reduction relative to the same purchase without that allowance. This is state-specific arithmetic, not a universal credit. Compare it with the private-sale proceeds and costs, rather than choosing whichever route has the bigger gross price.
The trade-in and private-sale guide keeps those routes comparable. Do not count the $750 example twice by both reducing tax and adding it again as cash received. If there is negative equity, carry the remaining payoff visibly into the funding arrangement instead of allowing the new payment to conceal it.
The final agreement has to match the compared offer
Before signing, reconcile the vehicle, price, trade allowance, tax, charges, amount financed, APR and payment count. A change in any of these inputs creates a new comparison. A lender disclosure can reveal an added product or extended term even when the displayed payment stays close to the requested target.
Keep the purchase, old-loan settlement and title-transfer records together. The seller’s receipt, lender credit and title release are different steps, and a promised payoff is not proof that the old account is settled. For an unresolved tax, title or contract interpretation, use the responsible authority or adviser with the records.
The loan’s total payments include its principal. The existing car’s sale proceeds must settle its lender and selling expenses first. These two accounting mistakes can make a transaction look thousands of dollars cheaper or more affordable than it is.
Questions people ask
Does the $21,570 example represent a typical used-car purchase?
No. It uses an assumed $20,000 price, Texas-rate arithmetic, a $100 placeholder and a named $220 inspection. Replace the assumptions with the final offer and destination requirements.
Is the lowest monthly payment the cheapest financing?
Not necessarily. Compare APR, term, amount financed and total payments. Extending repayment can reduce the installment while increasing interest.
Can I use the full $12,000 sale as a down payment?
Not if the illustrated $7,000 lender payoff remains due. The example leaves $5,000 before selling expenses and any payoff changes.
Does a trade-in always save 6.25% tax?
No. That example uses Texas's published rate and qualifying trade allowance. Other jurisdictions and transactions can differ.
Where these figures come from
- Motor Vehicle Sales and Use Tax Texas Comptroller of Public Accounts · comptroller.texas.gov
- Inspection Packages and Add-on Prices Lemon Squad · lemonsquad.com
- Used Auto Loan Rates, October 8, 2026 Navy Federal Credit Union · navyfederal.org
- Buying a Used Car From a Dealer Federal Trade Commission · consumer.ftc.gov
- Financing or Leasing a Car Federal Trade Commission · consumer.ftc.gov
Figures last checked October 2026.
