here's a couple of the ones I've posted that I like...
Cleaning rust off the body...
LINK
My clear roof mounted marker/ID lights...
LINK
The already requested frenched marker lights...
LINK To stay within the guidlines I posted, you could use a file, or a dremmel tool instead of the air cutoff that I used.
(texanidiot25's pic is better than mine)
Plywood bed floor
LINK This may come in over 50 bucks now, but with a sn=maller bed, or cheaper plywood, it can come in under 50 bones.
No thread, but junkyard van tilds are always a favorite mod of mine. I have never paid more than 35 bucks for one (bought 10 or so over the years).
Washing and a full detail inside and out is always time well spent IMO, and it's hard to spend 50 bucks in soap and wax, use an old T shirt for an application rag if you get to the $50 limit.
I could probably go on and on