RE: Sig kadet Lt-40
If you were to buy all the materials (or the factory parts) to build the plane, you would have many times the expense of the kit version. You can get individual parts directly from Sig.
Notwithstanding radio or mechanical failure, and with proper instruction, I doubt if you will ever "kill" the plane. As long as you have a supply of balsa and liteply you can repair everything on the plane.
My suggestion is to just have fun with the plane, and don't be worrying about crashes now. Crashes are a part of this hobby, but you should not preoccupy your mind with it. After you learn on the LT, you will probably, like most flyers, want to move up to a shoulder wing such as the Sig Mid Star, or even a low wing 4 Star.
Bob