The question is, would you have bid more on that bus? There is a little bit of art to bidding. You have to know how much that bus should sell for, and if you're willing to pay that price bid accordingly. Most of us stay just on the cheap side of what a bus is worth unless it's something that we've wanted for a long while.
The point is when proxy bidding you rarely can get away with bidding timidly. Sometimes the item falls in your lap for less than expected, but most of the time someone will bid you up to try and take the bus. Most will bid about four times against you, or snipe the bid at the end like what happened to you. If you had $200 more cushion on your bid you'd have probably won.
It's difficult if you're not used to the auctions. Sometimes there are people that get in bidding wars and prices go up two or three times the value of the item being sold. Set a maximum price you're willing to pay and make a proxy bid. It often pays to bid low, but be careful about making multiple bids. Sometimes an auction can come around and bite you.