One of the best sites for this is themeforest.com which specializes in all types of ways to make money from selling your templates, to selling mp3 files and other types of audio files to selling videos and so forth. They make a bit off you and then your able to withdraw once you reach a certain amount. Of course they take a small percentage out but if you are a popular developer it can really be a good way to make some money.
It's on themeforest.com but it's called the envato market.
It's on themeforest.com but it's called the envato market.