Here's my $.02...
The "fanciness" of the tank depends on how "well" you want it to look when you, or someone else, looks at it. Assuming the ball is a baby, you can start it out in a 20 gallon tank (with the possibility of getting a larger one later), with a tight fitting screen lid. You can have a dome light on one side for heat, and have a cardboard box (with a door cut in the side) on the other side to be used as a hide. Then, have a bowl in the middle for water, and it should be big enough for him/her to lay in and not be able to tip over. For substrate you can just use newspaper or paper towels (for easy cleanup)... Heck, you could even keep your ball in a sterilite tub with a heating pad at one end.
The only "real" thing to worry about is the type of substrate you use. Many pet stores will tell you to use aspen bedding and some will even say that you can use sand. However, be aware that these items can be ingested and could cause digestion issues!!!
If you want to make it look cool, while still being able to clean it easily, you can use the carpet that is sold in the pet stores, indoor/outdoor carpet from any hardware store (cut to the size of your aquarium), or you can even cut a couple pieces of linoleum tiles to put in the bottom (what I use in most of my "display" tanks). Many of the linoleum tiles can be purchased for $.50-.99 a tile and can be purchased in many colors to fit your "decor!"
Hides can be as simple as a cardboard box, something you buy from a pet store, or you can even find some nice flat stones and silicone some together. If you decide to use stones from outside, make sure you scrub them with hot soapy water, then heat them in the oven @ 400 degrees for about 30-45 minutes (this will kill any bacteria that may be living on the rocks).
The options are endless, but just look online and find what works for how you want it to look... If something doesn't sound "right" when you read it online, feel free to come back and ask.
Good luck and enjoy your new pet!!!
