earthworms have worked for me, and they are cheap. : )it depends on how large the water container is. it is reccomended change it every day, but i usually do it about 2 or 3 times a week, and i have a large bin in their tank. I would reccomend a filter if you get a larger water source so it can pump the water and catch alot of the crap. Also i use tap water as well, occasionally if i dont forget ill put this zoo med solution in it(its blue), but i usually just use straight tap water since i have a pump in there. just keep in mind a 30 gallon tank will only be good for maybe 3-5 months tops. I got mine a larger tank within about a month just because they need vertical not horizontal. I now have my beardie in my 55 gallon. i got my mister later on as well once i got a bigger tank. Get it off amazon, you can usually find one for about 80 as opposed to 120 on other sites. Also if you decide no mister you can always try a repti fogger. its about 50 and it works well but mine broke so thats the only complaint i have.