Regarding just bidding the highest you want to pay, you have to watch that too. I was(I believe) scammed withthatone once.
I was bidding on a bmx, £100 was my limit so I put my £100 bid on. At the point of my bid, the bidding was at around £35. I sat and kept an eye on the auction in it's last hour. The amount started to climb, and climb, and climb, in small increments.
It carried on going and went up to about £101. True to my intention, I had been outbid so I left the auction alone and started bidding on a second choice bmx I had seen. I went on to win this second bmx.
Going to my emails after, I noticed an email telling me that I had won the first auction. Reason being that the winning bid had been mutually retracted and so it automatically goes back to the next highest bidder....me.
This is also a known scam I found out. Sellers have dual accounts or get mates to bid in small increments higher until they find the highest real bidder. They then mutually withdraw that bid and it's back to the real bidder at the maximum they were willing to go to.
I complained, told eBay , threatened the seller etc and eventually got him to withdraw my winning bid .
I hate eBay(people)