Always be prepared to make the purchase. Although I wouldn't recommend buying the Z as soon as you see it, be prepared to at least leave $500 cash as a deposit. Also, you should have just offered the first guy $10K, $300 above what he was asking. Maybe at that point he'd hold off. I also think that a $500 deposit may have encouraged him to wait a week for the rest of the cash. There are a lot of nice TTZ's around, but if you have to wait to get the money, you're going to miss out. The nice ones don't stay on the market for long.