Saline solution

To those doing "moist healing": do you use a saline solution? If so, do you buy saline solution (e.g. at a pharmacy) or do you make your own? And if you make your own, how and using what kins of salt? The stuff from the store/pharmacy is pretty expensive, and if I keep doing this for a while, I might think about making my own solution (9 grams of (sea)salt per 1 liter water (boiled for a few minutes)). Not sure how "safe" that is but if done right, it shouldn't be that much different from the stuff you can buy.