Repairing a Broken Key on a Smith Corona Typewriter?

I have been calling around trying to fix a 1960 Smith Corona silent typewriter. I've been quoted about 100$ just to fix a typewriter that I purchased for 20$. So now I'm searching for some guidance. I have a key that is broken. It is not necessarily the actual lettering, but the lever underneath the key. I hope I'm explaining this correctly. Also the keys get stuck when I press on them.