Check out classifieds and what not I came across one from a guy that came into my store (PetSmart). He's in all the time and we got to talking and he sold me one of his 3 stage RO's for $50. I replaced all of the pre-filters (sediment, carbon and DI) for $45 and the RO membrane $50. So far I'm into it for $145 but sucks for me I was setting it all up today and found out the water pressure in my house is too low to run it. I had to order a RO booster pump for $85. So now I'm into it for $230. Still cheaper then it would have been if I bought it new.