The way I figure it, what was the verbal agreement prior to the deposit. How long were you suppose to wait for him ? Buyers do need to realize that when they put a deposit on equipment, that that money is gone if they fail to fulfill their end of the deal. On the other hand, if in fact you sold the equipment prior to the day the buyer agreed to pay you in full, I’d say just refund him the 100$. Just my 2 cents:)