RO/DI vs plain RO


New member
Moved to a small town in AZ a few years back and finally ready to start up a new tank. Trying to figure out the best way to get water. Nearest fish stores are in Tucson over an hour away, so trying to find a local solution instead of buying at a shop as I've always done in the past.
There some of those water stations set up around town that sell RO water at $1 a gal or so. Trying to figure out if "RO water" is good enough for corals or if I really need to have a home RO/DI canister system?
Currently planning on a 65 gal tank with sump so I know I'll be losing a gal a day or so to evaporation. My garage has a space for a work sink, is there any home RO/DI system that can plug into those pipes or do I need an actual faucet to hook into? Thanks much.