It seems you're really new to bitcoin mining.
Right now, there are two routes :
1. Bitcoin route :
ASIC, pre-order only for now. Will be released in October according to BFL
4 GH/s $149
40 GH/s $1200
1 TH/s $30,000
http://www.butterflylabs.com/products/
FPGA (will be obsolete in October)
Mod Miner Quad, 800 MH/s, 80 W, $1069
BFL Single 800 MH/s, 40W, $600
GPU (will be obsolete in October)
Speed varies between 212-685 MH/s, watt consumption is high.
2. Litecoin route :
GPU
Depends on the model, varies between $100 - $400
https://en.bitcoin.it/wiki/Mining_hardware_comparison