Spotify is an example, but you can find many others like Evernote, Steam or WoW. It depends on your users willing to pay on a monthly basis. But you are the one

Spotify is an example, but you can find many others like Evernote, Steam or WoW. It depends on your users willing to pay on a monthly basis. But you are the one that best know your product, if you say it'd difficult, it must be true :)