Try a local store, Autozone, Napa, Advanced Auto Parts, Carquest, whatever. My guess is you're looking at the group buys and comparing prices for high performance aftermarket parts to oem, and that's why they're higher. Carbotech brake pads are going to cost quite a bit more than mitsu ones, but they'll also outperform it by a large margin.
I bought rebuild kits for rear n/a calipers from a parts store last year for about $8/ea., and they had the pistons for an extra $20/ea.
O'Reilly Auto Parts
Or, if you'd rather not rebuild them yourself, they had reman. calipers for about $90/ea.
Autozone
I got 2 new rear rotors for $25/ea.
Advanced Auto Parts
The car's owner had purchased some cheap pads from autozone for $10-$15.
Try comparing apples to apples and prices should drop. Figure out what you want, what you're willing to spend, and how much of the work you want to do, and then decide upon the appropriate route.