Research

Set a total budget including tax, registration, insurance, and immediate repairsRule of thumb: add 10% on top of the sticker for taxes and fees, and hold back a repair reserve — most used cars need something within the first year.
Get pre-approved for financing from your bank or credit union if financingWalking in with outside financing turns the dealer's rate into a ceiling to beat, not the only offer. Never negotiate on monthly payment — that hides the real price.
Shortlist 2–3 models with strong reliability recordsOwner-reported reliability data and model-specific forums surface known failure years (a bad transmission year, a recalled engine).
Look up fair market prices for each shortlisted modelUse at least two pricing guides for your zip code, mileage, and condition. This number is your negotiation anchor later.
Get insurance quotes on the shortlist before committingPremiums vary widely between models and can erase a "cheaper" car's advantage.

Vehicle history

Get the VIN from the seller and run a vehicle history reportWalk away from salvage, flood, or odometer-rollback titles unless you're an expert buying at a deep discount. A seller who won't share the VIN is a seller to skip.
Check the VIN for open recalls on the NHTSA siteFree, takes a minute. Recall repairs are done at no charge by any franchised dealer — but you want them done before you buy.
Verify the title is in the seller's name and lien-free if private sellerAsk to see the physical title before the test drive. A lien means the bank owns the car; buying it without a payoff plan is how titles get stuck in limbo.
Read the Buyers Guide sticker on the window if dealerFederal law requires it. "As is — no warranty" means exactly that: every problem is yours the moment you sign.

Inspect in daylight, dry weather, with a cold engineRain hides paint flaws; a pre-warmed engine hides hard-start problems. Ask the seller not to run it before you arrive.
Check body panel gaps, paint match, and tire wearUneven gaps and mismatched paint say collision repair; uneven tire wear says alignment or suspension problems. Bring a magnet or paint gauge for suspected filler.
Check the oil and transmission fluid, and look under the car for leaksMilky oil suggests a head gasket; burnt-smelling transmission fluid suggests an expensive rebuild. Fresh undercoating can hide rust.
Check for flood signs: musty smell, silt under carpet, fogged headlights, corroded connectorsFlood cars migrate across state lines to launder their titles, and the electrical problems appear months later.
Test every electrical item: windows, locks, AC, heat, infotainment, all lights, every seat adjustmentSmall electrical faults are cheap to find now and maddening to chase later. AC that "just needs a recharge" usually needs a compressor.
Test drive for at least 30 minutes: cold start, city, highway, and hard brakingListen with the radio off. Note pulling under braking, hesitation, clunks over bumps, and any warning light — including ones that are suspiciously absent during the bulb check at startup.

Take the car to an independent mechanic of your choosing for a pre-purchase inspection$100–$200 for a lift inspection and scan. A seller who refuses a PPI has answered your real question. Never use a mechanic the seller suggests.
Have the mechanic scan for stored and pending trouble codesA recently cleared code history can mean the seller erased a warning light for the sale.
Get the findings as a written estimate for needed repairsThis is your negotiation evidence, priced in real dollars.

Open below market value and negotiate on the out-the-door priceAnchor to your pricing research minus the mechanic's repair estimate. Out-the-door means all taxes and fees included — dealers reintroduce hundreds in "doc fees" at signing.
Decline add-ons: VIN etching, paint protection, nitrogen tires if dealerExtended warranties are the one add-on worth evaluating — but read what it actually covers and price third-party alternatives first.
Verify the odometer reading matches the title and history report
Complete the title transfer and bill of sale correctlyBoth parties sign where the title requires; the bill of sale lists VIN, price, date, mileage, and both parties. In many states the seller must notify the DMV of the sale too.
Pay by cashier's check or bank transfer, never a wire to a "shipping agent"Escrow-and-shipping arrangements for a car you haven't seen in person are almost always fraud.
Confirm insurance is active before driving offMost insurers can bind coverage on a new-to-you car by phone in minutes; driving home uninsured is an expensive gamble.

Register and title the car with your DMV within the deadlineCommonly 10–30 days depending on state; late transfers mean penalties and sometimes a re-inspection.
Schedule any open recall repairs at a franchised dealerFree regardless of where or when you bought the car.
Do a baseline service: oil and filter, air filter, and any fluids the mechanic flaggedUnless the seller has receipts, assume the maintenance wasn't done.
Check the timing belt interval against the odometer if timing belt engineA snapped belt on an interference engine destroys it. If the belt's history is unknown and the mileage is near the interval, budget the replacement into your price.
Get a spare key madeA modern transponder or smart key runs $150–$500 at the dealer; having only one key is a lost-key crisis waiting to happen.
File the paperwork: title, bill of sale, inspection report, service receiptsYou'll want the whole trail when you sell it.