Dryer will not turn

Over the last few months we have been having trouble with our dryer turning without assistance. It would make the noise like it was wanting to turn but couldn’t. So we would have to open the door and manually turn the wheel and kind of give it a boost and then close the door really fast to keep it going and it would then work fine until it needed to be started again.

Well…now it wont turn at all…even with assistance. I don’t want to call a repair man because I know it will end up costing almost as much as a new dryer. Do you know what kind of part I might need in order to fix my problem?