I just won an auction on ebay.
I bid $15.03, and I was the high bidder.
With one minute left I bid $17.00, kind of to cover my action from a sniper.
With the 2nd bid ($17.)my bid went up to $15.50.
After the auction was over I was the high bidder at $15.50. The 2nd bidder was at $15.00. My question is why was my bid increased to $15.50. As I see it had I not put in the 2nd bid, I would have been the high bidder by 3 cents, and I would have saved myself 47 cents.
What am I missing here?

Thanks,
Ralph