I would be careful over leaving deposits with a seller. If you do that make sure whatever written agreement you have specifies when and how you get your money back or when the seller can keep your money and sell it to someone else. On another board someone left a $500 deposit on a $2500 bike but then changed his mind. He wanted his deposit back (wrongly in my opinion) but got very upset when the seller told him no. Because it all happened quickly he felt justified in asking for his money back. Most of the board members backed him up and some seemed to think the law backed him up. Didn’t feel right to me. What was the deposit for if he felt he could back out and get the money back?
In short, if you are planning on leaving a deposit put some thought into a written agreement before you get there. Save a lot of pain later on.