I'm trying to keep the cost as low as possible. That doesn't mean that I am cutting corners, but try to make do with what I can salvage or buy reasonably.
The frame is made of steel that I had around the shop, some of it used. Tires & wheels, used. Fenders, bought on ebay. Taillights, salvaged off a 59 VW bug. Some of the plywood I bought was from the discount rack, figured a busted corner wouldn't hurt since I was going to cut it off anyways, the rest was bought when it was on sale. Some of the dimensional lumber was also used, or bought on sale. Cooler, vintage Coleman from a yard sale. Matress, from the spare bedroom. Door hardware, won at the ITG (Thanks Grant)
Some of the lighting and odds & ends were salvaged from an old pick-up camper. Windows were salvaged from a 65 VW camper van. Stabalizer jacks salvaged from an old pop up camper.
Of course not everyting is used or bought on sale.
The aluminum, most of the trim, hinges, baltic birch plywood, axel, coupler, and wiring are all new. Hardawre, paint, varnish, glue, etc. of course all new. Several new tools were bought for the project (clamps, router bits, saw blades, etc.). Had to buy a hitch and wiring for the VW to tow it.
Not sure what my final cost will be, but I'm hoping it's well under $2000.