In all honesty, there are very few LFS I'd trust when it come to RO/DI. When I used to purchase RO/DI, I brought my TDS meter one time and I was getting a reading of 100+. If I were you, I'd invest in an RO/DI unit if you could.
I agree with above. You should get an RODI unit rather than rely on an LFS. There is a higher up front cost but it will be cheaper and better for your tank in the long run.
Reef lounge is around Anaheim. Seaside Tropical Fish is in HB. But I agree with everyone else, and get an RO/DI unit. Doesn't have to be fancy either but you'll get the best water quality you can by doing it yourself.
Water from those vending machines will more than likely have a TDS of 20 or so. Ideally you'd like to have your ATO water at 0 TDS to prevent algae blooms.
I'm in Fullerton. I always have 100g of rodi on hand in my large jug. I can sell for whatever a fish store would charge. I think its 25 cents a gallon.bring a few jugs and fill em up.