Compare two real candidates
“New” and “used” are categories, not budgets. Choose a model, trim, mileage, and written price for each candidate. Keep a separate column for what you know and what you still need to check. A low advertised price is not a complete comparison if one car includes options you do not need or the other needs tires immediately.
The FTC’s used-car guidance recommends budgeting for registration, insurance, fuel, and maintenance alongside the car itself. Ask for the used car’s Buyers Guide and warranty documents; do not assume a “certified” label describes the same coverage at every dealer.
Build an ownership worksheet
For a cash purchase, a useful planning equation is:
Purchase price + taxes and fees + running costs − estimated resale value = estimated ownership cost.
For a financed purchase, add financing costs without counting the borrowed principal twice. A cash-flow budget is different: it tracks your down payment and actual monthly bills, not depreciation as another monthly payment.
| Item | What to record for each car |
|---|---|
| Purchase | Written out-the-door price, including the same optional equipment |
| Financing | APR, term, amount financed, and total payments |
| Running costs | Fuel, parking, registration, insurance, and scheduled service |
| Repairs | Inspection findings and a reserve for uncertainty |
| Exit | A conservative resale estimate after the same number of years |
Try a simple sensitivity check. If a used car is $5,000 cheaper to buy, ask how your decision changes with $2,000 of extra repairs and a $1,500 lower resale value. Those invented worksheet inputs leave only $1,500 of the initial advantage before other differences. They are a scenario, not a prediction about either car.
Check fit before choosing a winner
Compare the exact engine and transmission in the DOE/EPA vehicle comparison tool. Your route, weather, and driving pattern can differ from a test estimate. Get model-specific insurance quotes; CarInsuranceSherpa covers the insurance side of ownership.
A newer car may still be the wrong car if it does not fit your parking space or passenger needs. An older one may be poor value if deferred work consumes the apparent saving. Test child-seat access, visibility, cargo space, and a representative drive before treating the worksheet as a decision.
Your next step
Request two out-the-door quotes, then arrange an independent inspection for the used candidate. Leave uncertain costs visible instead of replacing them with zero.
Sources & further reading
- FTC: Buying a Used Car From a Dealer
Accessed 2026-10-07 - DOE and EPA: Compare vehicles side by side
Accessed 2026-10-07
Prepared by Sherpa Desk from public sources. No claim of hands-on vehicle testing or professional financial review.
