From what I've gathered tap water is fine for reptiles. I personally buy the big jugs from the store for mine.

As for the useless products. Ball pythons are very resilient snakes. They honestly can live in horrible conditions. Look at some of the craigslist rescues. It's amazing how they can survive some houses. The "useless" products are a good way to get people not educated in reptiles to buy their products. It's the same reason why there is a picture of a snake on heat rocks, because there will always be people who buy them unfortunately. It's sad, but there's nothing anyone can do about it except try to educate people on, if anything, bare minimum care (example: regulated heat source, water, hides, etc) and also not buy those products.

You aren't the only sucker, I had a TON of useless stuff that I bought that are since in the trash or returned.