Any suggestions on how to avoid scams?
As a seller, my biggest concern is getting funds from the buyer.
When I've sold in the past, I've always had clear title (paper). Create a "Bill of Sale" using any one of many available templates on-line for your state. Ask to see Photo ID of the buyer to get name and address to copy on to the bill. Normally we meet at my bank (Wells Fargo) during regular bank business hours, and they either provide a cashiers check verifiable by Wells Fargo, or wire transfer the funds into my account. (Just because it says 'Cashiers Check', doesn't mean it's real).
Once the funds are verified, I sign both copies of the "Bill of Sale", have the buyer sign both copies of the "Bill of Sale", sign over the title document, remove my tags, and hand over the keys. (Don't let the buyer "borrow" you tags. In my state, it's illegal) Then, notify your insurance company, DMV, and your locality (if you pay personal property taxes on vehicles) that the vehicle has been sold.
I keep an Excel spreadsheet detailing all of the maintenance/repairs performed on the vehicle either by me, the dealership, or a 3rd party mechanic, down to oil changes and tire rotations. I scan all receipts for parts and maintenance supplies, invoices for work. I print all of these and hand them over to the buyer.
Also, have all paperwork necessary to transfer warranties, service plans, etc. available to hand over to the buyer. Research what you need to do in advance. Do them a favor.
Under no circumstances do you let the buyer take possession of the vehicle until the above is completed. DO NOT agree to ship a car to anyone, whether you coordinate, or they offer to coordinate. Big scams exist around fake shipping companies, and fake funds. Last buyer I had out of state flew into the closest airport, and I picked him up and conducted the transaction as listed above. He drove it home to Texas.
If you don't have clear title (bank payoff), then it gets complicated, unless the financing is at the bank you are conducting the transaction, and you can get the buyer proof of payoff. You might want to use an escrow service (Escrow.com), like eBay recommends.
Wherever you list your car online (I use Cars.com), you will get fake, scam text messages and phone calls almost immediately. Someone is always scouring the list looking for new suckers.
Good Luck!