I already have a laptop so what else do I need so I can check for any codes the computer might throw? And where is cheapest place to purchase? Thanks

 

Have you tried here?
http://www.carputing.com/

 

These guys sell the cables and have the free software to download. Check em out!

http://www.akmcables.com/

 

FreeScan (the price is right), TTS Datamaster (free download and up to 20 uses before payment required), Diacom (seriously outdated DOS system - ridiculous price).

Some of these links are outdated, but it might get you pointed in the right direction:

http://members.aol.com/FWForsythePE/HowTo/Scanner.htm

 

I used AKM Cables and FreeScan.....<$100....AND when it allowed me to buy Madwolf's internet tune for only $60 ...but I see now that you have a 355, so you probably wouldn't want a mail-order tune, hehehe