I use reverse osmosis filtered water from a machine. It works well and is cheap. You just refill your jugs. Your local fish store might have easier to handle and better pouring jugs designed specifically for aquariums. Mine does. Then you gotta have the water chemistry right. Neutral pH is best and easiest to go for with most fish. Look into Seachem Neutral Regulator for balancing your pH. Seachem Replenish will give the water the minerals it and the fish need. You put this stuff in for however much water you remove. (they don't evaporate) I change my water once a month on the 15th and change my filters on the first, along with rinsing out the whole pump system. Never use soap on anything involving fish.
Better to use "RO" water than trying to treat tap water which can be very bad for fish and humans too in certion places. I'm told it was once possible to use tap water and let it sit until the chorine naturally leaves. Now it has chloramines which are toxic to fish and microorganisms, including your benificial bacteria. Chlorine is obviously bad as well. But yeah just do 25% water changes once a month should be ok. Never clean everything at once. The stuff on your rocks, ornaments, fake plants, substrate, etc. are all part of your natural filter. Never a good idea to clean all the stuff at the same time. That's why I don't do water changes and filter changes at the same time. I learned some from books and Internet articles, my Grandma, but most of it I learned from Aquatek. Dunno about salt water though. Could get more involved and difficult. I know keeping marine fish, and especially reef tanks, is "hard mode", so I don't mess with that.
But yeah you don't have to use distilled water. Just refill jugs at Glacier machines or any other machine that says somewhere on it that the water is reverse osmosis filtered.
Now I am no master, so you may want to get with someone with more experience, but just letting you know what I DO know about thanks to my years of doing this and talking to others with even more years in the hobby.