One more note on auction buying on eBay.  There is another dirty
trick to watch for: a seller can arrange for someone to bid after
you have put in your maximum bid to find out what your maximum is.
The confederate bids very high and that reveals your top bid, then 
the confederate withdraws his bid, leaving you as the winner, but
always at the maximum.  An irritating trick.  I only noticed it when
I won several auctions for small stuff, but always at that top price
from one buyer.

One way or another, the system can't force you past your top price,
so if you really bid the very most you are willing to pay, you need
not fear the snipers.

Jim Katz