Also let's backtrack quite a bit
Step 1: Go to a local lake or landscaping shop, get some decent sized river rocks
If you got rocks from a lake, let them air dry for a bit then soak them in hot (not boiling) water, then let them air dry again
Step 2: Get some play sand, then wash said sand in a clean bucket until the water in the bucket is no longer dusty, repeat the process until you have as much sand in the tank as you'd like
Step 3: Scape your tank, build up the rocks as structure to create hiding places for the fish. You can also add fallen branches of oak, beech, cherry, or maple to the tank, and dried leaves of the same trees as long as they're collected from an area that is not sprayed with pesticides or fertilizers. They will sink within days if you add them directly to the tank, but if you want you can boil them to make them sink. Do not add the boiling water to your tank, it will crack. Do not use wood or leaves if they have fungus or insects in or on them. Do not worry about the tannins that are released off the leaves or wood.
Step 4: Buy sponge filters, set them up in your tank
Step 5: Go to your local fish store and see if they have sponge filters in their tanks and ask if you can wring one or two out into a jar
Step 6: Dump the jar into your tank with the new sponge filters and let it run for a bit.
Step 7: Put whatever other equipment you had back in, like heaters or powerheads. Putting the heater near the powerhead will help with creating an even/optimal temperature throughout the tank.
Now you have a functional, naturalistic and good looking tank that the fish will be happy in. This process can be done within a week, not even taking the whole week. This process should (minus gas) cost at most $20, unless you bought the rocks, then it might cost a bit more (by like $20)
Also don't rely too much on the powerhead sponge combos for filtration. They aren't as good as actual premade sponge filters. Actual sponge filters cost around $10 for a 4 pack. No need to diy
The intense blue bulbs aren't good for the fish, and the dome lights will cost you more overtime because of replacing bulbs. Just get a cheap LED strip off Amazon.