Got photos? It could be worth as little as $100 if it needs a lot of work but if it is in mint condition, maybe $700. The C Melodies have not had a big following until lately. It is probably satin silver plate with polished keys and may have a godl wash (plate) inside the bell. Having the case is important regardless of condition. To clean, use a soft silver polish like Haggerty's liquid but do NOT get it on the pads or keywork where things move or they will cease to move! These C Melodies are between an alto and tenor and play in concert pitch like a piano, flute, violin, etc. Popular for church use as you can read off the hymns.