You will regret not using RO
water. You will spend all of your time fighting algae breakouts.
Your tank is 37 gallons. Even if you did 20% weekly water changes, which is on the high side. You would only need 7.4 gallons per week, add a gallon or 2 for evaporation / top-offs. Let's just say (10) gallons. At the supermarket near me, the water costs $.29 per gallon if you have your own jug, and $.39 per gallon if you don't. The most you should pay is $4.00 your first week, and $3.00 per week after that. And again that is doing religious large water changes.
If you are going to have a hard time coming up with that amount of money, I really think you may want to take a look at the real costs associated with this hobby.
I wish you the best of luck, and keep the questions coming. I'm very happy to see that you've done your research and your stocking list looks great.