I don't know anything about Music Medic's "repair kit," but I say start with any basic tools you have, and go for it. If you find you enjoy it, you can always expand your repair bench with tools as you need them, and nothing beats experience. Take the horn apart, clean it, put in new pads and material, and then start diagnosing problems as you find them. These days there are plenty of tutorials online.

I thought the same thing so I purposely bought the worst C-Melody I could find on Ebay. If I am going to learn repair, then get one that really needs it. Big mistake. Start with a working horn that needs a bit of repair and take it apart, clean, new pads where needed, regulate it, etc.