i've got about $300 into it so far:
2-12 gallon tanks
10 switches with chrome extensions
1-250 psi water trap
im expecting to pay about another about $1700-$1800 on:
4-blitzluft 337 compressors
4-slam specialties HS bags (dual 1/2" ports)
all 1/2" fittings and hose (hopefully he'll throw in another 60 ft. of hose and a couple of at least 175 psi pressure switches...we'll see...)
8-blitzluft 1/2" valves (want to get another 8 in the near future -8 up, 8 down)
and front and rear brackets for a 66 impala (i think thats it, if im not forgetting anything)
then i also plan on getting a deep cycle marine battery in my trunk, an isolator, and metal to reinforce my rear wheel arches (to be safe), put a scrape plate, and maybe reinforce my a-arms. (about another $300 or so.
then my friend is going to do it for me, but he'll probably end up charging me about $200-400.
so total, max, i say somewhere around $2800 when all is said and done (not including the 8 valves i plan on getting later on, about another about $350 or so).