Cheap way to get HP?

Im looking to gain some horsepower in my GT, but only have about $100 to spend for now. I know this is nothing, but i was wondering if there is any little part, or worthwhile upgrade that will do anything for me. Is there any single item worth getting for that amount?
 
Anything that you can buy that will help it breath. Skip buying anymore of the looky-loo stuff. There isnt an ounce of HP coming out of any of that.. Save it for later. Cold air induction can be had for 125-150 if you shop it a bit. Hunt around on EBAY. Used is alright as long as you get all the pieces that go with it. The rule of thumb I go with is start from the tailpipe and work backwards. Putting gears and stuff like that is good but you need to open up the air capacity first. Then go to work on the torque. Aluminum where you can, gears etc... Hunt around for the deals, they're out there. If it sounds way too good to be true, post it on one of these threads and see if anyone else has been burned. We all have stories to tell.. I have a large cardboard box of "deals" in my garage right now.
 
o/r x pipe for $80 put me from consitent 14.0's with a best of 13.99 to consitent 13.90's with a best of 13.81. No change other than o/r x pipe. Since adding welded in Magnapacks I've run a best of 13.69 and run consitent 13.7's/13.8's. Packs cost me $160 plus $50 for welding, and o/r x cost me $80 plus $30 for MIL's.

$290 got me from consitent 14.0's to consitent 13.7's. Not bad in my opinion.