For those that have bought from private sellers, do any of you bank through your brokerage? How did you pay? I use Ameritrade, which doesn't issue cashier's checks as far as I can tell. Do apps like Venmo fill such a need?
I've only bought from a private seller once. I paid cash.
I've also sold several cars to private buyers. The first couple times I didn't really know what I was doing, and I accepted cashier's checks. Luckily I was dealing with honest people. Since then, I've only accepted cash. I might accept a cashier's check or certified check if I went to the bank with the buyer and verified that the check was real and the person had the cash to back it up. But no way would I take any kind of check from a seller under any other circumstances, unless it was someone I know and trust.
I've bought 6 cars from private parties (2 from ads in the newspaper back when those existed and 3 from craigslist/autotrader, one from a family member). I paid cash for 3 of them and cashiers checks for two of them, meeting the person at the bank for the transaction. The family member got a personal check. I've also sold three cars, two via craigslist. Got cash for two of them and the third was sold to a friend who I think paid me with a check.
It looks like the OP has already found a car, but here is my take if anyone is interesting.
1) Know what you're looking for. When I buy cars, I tend to fixate on a specific make/model with a range of years. Google for what the known issues with that car are and see if they've already been encountered. For example, years ago I really wanted an Audi Allroad. The airbag suspension was a known weakness. I found one with an extended warranty where the compressor and one of the bags had been replaced already. The second front bag ended up being replaced within 6 months of my purchase under that warranty. Check the forums for that car, someone may have done a checklist of things to look for.
2) Carfax. Definitely worth it. If it's been wrecked, even if not a salvage title, you may want to walk away depending on the severity.
3) Test drive. I've never had problems with the sellers allowing me to drive the car, sometimes they ride along, but not always.
4) Get a professional inspection. You probably need to have given them a firm offer and a deposit before they'll let you do that. (Note, I have not done this myself. lol)
5) Check the title against the VIN on the car. I screwed myself on that one 25+ years ago when buying an old used car. Probably less of an issue now, but on the car in question it was two pop rivets to remove the VIN and it wasn't until years later I discovered that not only was the VIN missing, but the title had an extra digit from what it should have.
6) Check your state laws on whether you need the title to be notarized when you buy.
7) Depending on your comfort level, meet in a public place to view the car, especially if you're walking around with a pocket full of Benjamins.
8) If the car is > than $5k, I'd rather pay with a cashier's check, so I've gone to see the car with about $1,000 in cash for a deposit. Get a receipt for that deposit.
9) As others have said if there is anything hinky in the communication (story changing, poor communication, don't have the title, etc) just walk away.
10) I've never bought a car that had a loan on it, so I'm not sure how to deal with title issues. (They need to pay it off to get the actual title, which they might not be able to do without your money, which you might not want to give them without getting the title immediately.)
When selling, I've only sold cars cheaply at the end of their lives, so I've been pretty open. That said, I've gotten cash for all of them, except the one I sold to a friend. Again depending on your comfort level, you may want to meet at a public place like a bank parking lot. Maybe bring a friend/spouse. Have your title ready and with you when you show the car. Take lots of pictures in good light (amazes me that people advertise on craigslist with one exterior photo). Bring a carfax report of your own car (two of the cars I bought the owners provided this and it really gave me more confidence). If they test drive, check their license and ride with them. The only contact I give on craigslist is email when I'm selling until I get comfortable with them. You will likely have some scammer reach out to you saying they want to wire or paypal you the money and have a freight company pick it up. Say no, you only deal with people in person.
Now, is it worth doing this on both sides? Absolutely! You're talking thousands on each end of the transaction for not much work. When I bought my german sports car years ago before finding MMM, I paid at the high end for private party, but that was still thousands less than the low end of a dealer sale. I hate dealing with sales people so I'd much rather buy from a private party. Maybe I've just been lucky but I've never had a bad experience except for the old car with the missing VIN.