Do hermit NEED salt water?

i know they need distilled water. so i am 100% sure i can give them that with no problem. but salt water in my location is kinda expensive for like 1 bottle. i know there is a mixture you can add to water to make it fine for hermit , but are those any good. Because they are like 20 dollars and i don't want to spend my money on that. so i was wondering, will they die if i just give them bottled water?