I used a lot of infill to make mine heavy I picked a weight I wanted and adjusted the slicer until I achieved that weight. How much filament you will need will be determined by the settings you use. The parts outside of the filament cost me around $100 but you can certainly shop around. Oh, and you can make it a n y c o l o r you want! I can't tell you the exact cost of this. This isn't a cheap project, but you'll end up with the satisfaction of making something awesome for your amazing cat(s) and having a sturdy cat wheel.
Please scroll down and read over the hardware needed. *(These are files for 3D printing, you won't be shipped a cat wheel!) If you purchase my files, you agree to not sell or share them, including the printed wheel itself. People asked to buy the STLs when I posted a video on Facebook, so I've uploaded the files on Cults3D. I won't name the company, but they are the first one to show up if you Google 'cat wheel'. I had already purchased a cat wheel but it spun poorly, didn't have a stable base, and I hated the fact that they used fiberglass in the rails without warning people and it messed up my hands.
This started as a personal challenge as I, a.) Made an impulse decision to buy a 3D printer, b.) Wanted to learn Fusion 360 to make something useful, and c.) Wanted to replace my existing cat wheel.