How do you buy a car?

Buying a car involves four sequential decisions: set a total budget (not just a monthly payment), choose new vs. used, secure financing before stepping into a dealership, then negotiate the purchase price and trade-in separately. The order matters — financing clarity before shopping prevents the most common and costly mistakes.

Most people overpay for a car not because they negotiated poorly at the last step, but because they skipped the first two. Walking into a dealer before you know your budget ceiling and have financing in hand shifts every conversation to your monthly payment — which dealers can manipulate through term length and add-ons. The FTC's car buying guide and the CFPB's auto loan resource both identify pre-shopping preparation as the single biggest lever buyers have.

Step 1: Set a total budget, not a monthly payment target

Start with what you can afford to spend in total — purchase price plus taxes, title, registration, and documentation fees. A monthly payment target alone is easy for dealers to game by extending the loan term. Use the loan amount, interest rate, and term together to understand total cost. A common guideline: total vehicle cost (purchase price) should not exceed roughly 15-20% of your gross annual income, though your actual budget depends on your full financial picture.

Step 2: New vs. used

New vehicles: manufacturer warranty, latest safety features, sometimes promotional financing — but steep early depreciation (often 15-20% in the first year).
Certified pre-owned (CPO): dealer-inspected used vehicles with extended warranty coverage; a middle-ground option.
Used vehicles: lower purchase price, slower depreciation from your ownership date — but potentially higher maintenance costs and no manufacturer warranty on older models.
Check vehicle history reports (VIN-based) and have a used vehicle independently inspected before purchase.

Step 3: Get pre-approved before you shop

Apply for pre-approval from a bank, credit union, or online lender before visiting any dealership. This gives you a confirmed rate and maximum loan amount to shop against. Dealer financing can be competitive — but you'll only know that if you have something to compare it to. Apply with two or three lenders within a 14-day window; under FICO's rate-shopping rules, those inquiries count as one. See how to get pre-approved for a car loan for the full process.

Step 4: Negotiate purchase price and trade-in separately

Negotiate the out-the-door price on the vehicle you're buying first. Once that's settled, discuss your trade-in — or, better yet, get a firm trade-in offer before you start price negotiations so the numbers stay separate. Bundling both in the same conversation makes it easier for the dealer to shift value between columns. See how to negotiate a car price for specific tactics.

Step 5: Review the finance and insurance (F&I) office

After agreeing on a price, you'll sit with a finance manager who may offer add-ons: extended warranties, GAP insurance, paint protection, tire/wheel coverage. Some add-ons — like GAP insurance on a loan with minimal down payment — may be worth considering; many others are overpriced and optional. Review every line item. The FTC advises reading the full contract before signing and not feeling pressured by time constraints.

What regulators say about car buying

The CFPB recommends arranging financing before visiting a dealership to understand your budget and compare any dealer-offered financing against an outside offer. — CFPB
The FTC advises consumers to research a vehicle's price — including dealer invoice, incentives, and local market data — before negotiating, and to negotiate the purchase price separately from trade-in and financing. — FTC
Under the Truth in Lending Act, lenders must disclose the APR and total cost of financing in writing before you sign — review these figures before completing a purchase. — FTC

Key takeaways

Set a total budget ceiling before you shop — monthly payment targets are too easy to manipulate through term length.
Get pre-approved from a bank or credit union first so you have a rate benchmark when dealer financing is offered.
Negotiate vehicle price before introducing trade-in or financing — keep each conversation separate.
Review every add-on in the F&I office; most are optional and many are available cheaper elsewhere.
Take your time: the FTC advises not signing until you've read the full contract and understand every cost.