On ebay, how do i turn down a best offer?

two days ago, i put in a best offer of $200 for 2 gwen stefani tickets. i forgot about it, and even at the time i doubted it would go that low. and this morning, i bid on 4 damien rice tickets for $200 and won. i can't really afford to go to both these concerts, but that's my fault. i got a message from the gwen guy saying he'd go down to 250 if i paid through paypal. i told him i wouldn't extend my offer past 200, and i thought that would disinterest him. but instead, now he offered to go to my low price through paypal. i don't know what to say! i don't want bad feedback and i don't want the guy to get upset with me either :( please help