Im just south of Chicago and have never paid more than $1 per gallon.. I always pick some up for between .88 & .99 cents per gallon..
The main question is: Did any of You guys checked it in a lab?
Yes, and it sure fails the tests for water for injection. But it is good distilled water.:)
Good question because the quality of destilled water can vary enormously. But this is the same with R.O. water. I am using Brita (TM) water which is enough filtered to get rid of all regular problems in photography and it is very suitable for use of "photo" water. One Maxtra filter can do about 80 ltrs. and it costs about Eur. 4,00. About Eur. 0,05 / ltr. and always available. The end quality also depends of the type of input water but here in Holland it is pretty good. In Ukraine it sometimes is a problem in a high amount of iron (rusty tubes).
We have a condensing dryer, though ours is rigged to pump the water into the washing machine's drain. Given the gunky wet lint that accumulates in the condenser, I don't think the water from it is something I'd consider for my film, but "mileage may vary".
As for distilled from the grocery store, it's labeled as distilled, and the label further states "purified by steam distillation". Sells for right around 1 USD per gallon/3.7 L around here, FWIW.