Re: Private sale terms
No matter what you think the agreement is, or what is said to each other... When selling, I always write out a receipt for the deposit that explicitly states the conditions agreed to.... I sign it, have the purchaser sign it, give the purchaser the original and keep a copy for myself. In there I say the serial number / VIN, what the agreed selling price is, how much was deposited "leaving a balance of....", how that will be paid, when it will be paid and the date by which the remainder must be paid and the item moved, and that the purchaser will forfeit their deposit it these conditions are not met. I think by having something in writing, it greatly decreases the likelihood that the purchaser will change their mind and expect you to understand and refund.
By the way, write it out as a "Receipt for Deposit"... NOT a bill of sale. They get bill of sale and title etc. only when it's paid in full. One thing to bear in mind though, is don't make a purchase agreement with a minor... they can't be held accountable and you'd be obliged to refund... This happened to my Dad once.. he took a deposit from 16 y.o. kid on a car.... Kid changes his mind, parents say give him his deposit back... My Dad says no way (had turned away other buyers), but they threaten to push the issue with their lawyer, my dad calls his, and in 30 seconds lawyer says, just give the money back, a judge would strike down the contract with the minor. So, if a minor is involved, tell them to bring their parent/guardian and sell to them instead.
Having a deposit that is refundable serves no purpose. Exception is if a water trial, mechanics inspection etc is failed, but that should be stipulated in the receipt of deposit, (along with who is intending to pay for the inspection). I have heard of buyers asking if the seller is willing to have a mechanic check it out, but then assuming that the seller is willing to pay for the inspection!? I have driven vehicles I'm selling to be inspected by a prospective purchaser's mechanic, but I would never give them the keys to take the vehicle/boat whatever on their own.