Simple, use your bank. Banks have all the safeguards in place to ensure the funds from the buyer make it to your account and many can also notarize title work etc. If there are any outstanding loans your bank will ensure they are paid off as well as part of a settlement. I think with a $20k TT your dealing with a local buyer so CG and FB marketplace might be better venues. Plenty of money transfer apps (Zelle, virtual wallet, Venmo etc). All these link to your bank account and you can verify funds in seconds. In person might also be a cash deal. Scams typically happen with a "virtual" buyer. For cars and RV's I like to deal in person. It's fine to communicate virtually, but when it comes time to exchanging money, do that with them standing there. Often I choose to do it at my bank.