Starter Problem 1981 Corolla

I have an 1981 Corolla DX, I have a problem, it's hard for me to start the engine, there are always annoying noises on the starter dynamo. Sometimes it won't even make any sound (silent, just like it has no batteries at all). I've checked all the cables already and they are fine. Is it the dynamo? How much wil it cost me if I really do have to replace it?