What he said.
Tire prices vary vastly depending on tire size and performance you desire. If you're looking for a decent upgrade from your stock tires while keeping the same size, I've had a few people recommend Falkens. I'm not sure which models come recommended, but rumor has it you can pick up some decent performing tires for a low price from them. Michelin Pilot Sports also come to mind, but they may be more than you want to pay.
Performance tires easily go anywhere from $30/tire to $150/tire. Usually the $150/tire are the UHP tires running sizes such as 225/40/18.
I'd recommend you check out
www.tirerack.com for some tire info, they've got a good selection and I've had a few people recommend them very highly. If it does nothing else for you, it'll at least give you a good idea of prices.
b