Since you live in Nevada, the water bill may be much more of a factor than it is to some of us. My water bill only runs about $35 a month - and I have a pool that I am always adding water to, as well as two aquariums to supply. It may be another matter entirely on your end. RO/DI systems do waste a lot of water - unless you can find a use for the waste water and not just let it run down the drain.
The equipment though is not really expensive. You can get a good 4-stage filter system for just over $100.
Here is my sons nano. I have taken over the job of water changes and taking care of it since when he was doing it you couldn't see in it. I think it is finally presentable.
Your son's tank has become your chore!! How funny!!! Had it been a dog, things would probably have been easier!!
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I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them. -Thomas Jefferson