Where can I buy s4 cams for a good price?

wrong place.. try groupbuy

Not in the SR20VE forum. Check the Classifieds and Group Buys forums.

There's a group buy going on right now:
http://www.sr20deforum.com/showthread.php?s=&threadid=42442
$495 shipped.

PM Andreas Miko he can get them for you.