It’s been paid for with either cash or cashiers check. Of course most of the cars were under $5k because I keep cars till they’re worn out. (more than 10 years old, etc.)
We went, together, to AAA, to retitle the car. (Faster, easier than DMV if one or both parties are AAA members.)
This is important for the seller – if the new owner does not retitle it in their name, and you have not taken the step to notify the DMV you sold it – any parking tickets they acquire get mailed to you, and you’re legally liable for them. My nephew made this mistake…. cost him several hundred dollars.
Back in the pre-craigslist days I used the auto-trader. On the 2 cars we sold we had the best luck with Craigslist.