A used car purchase is one of the largest financial transactions most people make outside of housing, and it is also one of the most negotiable. Dealerships and private sellers both have flexibility in their pricing that they will not reveal unless a buyer understands what the car is worth and is prepared to walk away. The research phase, not the negotiation itself, is where most of the money is saved or lost.
Know the fair market value before you go anywhere
Kelley Blue Book (kbb.com) and Edmunds both provide fair market price estimates for specific used vehicles based on year, make, model, mileage, condition, and your zip code. These are not perfect but they give you a realistic anchor for what the car should cost. If a dealer is listing a car at $4,000 above Edmunds estimated market value, you know that before you walk in. Buyers who arrive without this information are working from the seller's framing rather than their own.
Get a vehicle history report
A Carfax or AutoCheck report for any used car you are seriously considering costs around $40 or less and shows accident history, number of previous owners, whether the title is clean, service records if available, and whether the odometer reading is consistent with the vehicle's history. A car that has been in a significant accident, has a salvage title, or shows signs of odometer fraud is worth considerably less than one without those issues, regardless of what the seller is asking. Many dealerships provide this report for free; for private sellers, paying for it yourself is worthwhile.
Have a mechanic inspect the car before you buy
A pre-purchase inspection from an independent mechanic, not the dealer's service department, typically costs $100 to $150 and can reveal mechanical issues that would cost thousands to fix. Any legitimate seller should allow this inspection. If a seller refuses or creates pressure to skip it, that is a meaningful signal. Issues found during the inspection become negotiating leverage: if the mechanic identifies $800 of deferred maintenance, you have a documented basis to ask for that amount off the price.
Negotiate the price, not the monthly payment
Dealers prefer to discuss monthly payments rather than the total price because the monthly payment can be adjusted by extending the loan term rather than reducing the price. A $400 monthly payment on a 72-month loan is more expensive total than a $450 payment on a 48-month loan. Focus the conversation on the out-the-door price, which is the total including fees and taxes, before any discussion of financing. Once the price is agreed on, then evaluate the financing separately.
Get your own financing before you go
Getting pre-approved for an auto loan through a bank or credit union before you visit a dealership gives you two advantages: you know your actual interest rate before the dealer presents theirs, and you are not dependent on dealer financing if their terms are worse. Credit unions in particular often offer lower auto loan rates than dealerships. You can use the pre-approval as a floor and take the dealer's financing if they genuinely beat it.