I give $117 for the last one i just bought, a 6 stage, supposed to make 100 gpd, and it may not be that capacity but its relatively fast...For me to buy RODI water its a 120 mile roundtrip to town, and the LFS that sells it is only open Tues thru Sat from 12 to 7 so it screws up a whole day, and considering my vehicle is not an economy model I will burn more gas and wear and tear on the vehicle than what the water costs........I have two RO/DI units now, and I have to think with gas saved and time its already paid for itself and the 2nd should not be all that far off in paying for it self either.