Just bought everything for mine. 4 pumps(Jabsco Ballast Pups) at $179 each, 4 fatsacs one of which was custom ($450? total), then fittings, hose, pipe. You could probably go cheaper, but figure about $1000 if you do all the work.
Ive got a 03 v210 that came with the front sack I just got done adding rear ballast myself.Bought 2 jabsco ballast puppys off ebay.Got one for $80 the other for $170 both brand new.Running 2 coverless flyhigh sacs 275LBS each there 16x16x30 perfect fit.Fittings,hose,wire,sacks and pumps all under $600.Know Ive got 800lbs of automatic ballast I still fill a 580 fatboy for the mid floor.