Cheap but good ebay finds.

99% of the auctions posted in there turn out to be not so good of deals because more people see them....but buy it now stuff is awesome lol
 
Not to toot the guy's horn but Laz down at GT Thunder can make a poly belly skid for a blaster for $25. Cut to fit the frame, you drill your own holes.
(because I paid $60 for my swinger skid I'll be damned if Id pay $60 for my belly skid too)