Believe me, i understand wanting to save some cash and get the most you can with what you want. That said, I dont think i would base my port guy based on the cheapest price. If done wrong, the bike could very easily run worse and make less power than stock. Read through some posts on here you will see lots of names. Call them and see what they say.
List off the top of my head in no special order.
FAST, K&T, passion, herrjuggs, A&S, Nate Mccoy, LC performance, flotec, redline, white knuckle the list goes on and on. Cheapest isn't always the way to go