As for the "not many parts to these things", well, they have to have steering, suspension, drivetrain, electrical, body, seats, windshield and brakes.
The T-bucket is probably the most basic and elemental car, and those kits are getting expensive too.
http://www.speedwaymotors.com/T-Bucket-Kits.htmlYou can save some money by scrounging and building yourself, but all those elements must be there and look right. You can't just buy a Dakota, tear off the body and slap a 34 Dodge PU shell on the chassis. It doesn't look right.
EXAMPLE
https://board.moparts.org/ubbthreads/show...rue#Post7319099Here's a Model A build
http://www.jalopyjournal.com/forum/showthread.php?t=482087