I would like to build a 'homework-helping' community site, where students provide simple services for each other and earn a non-monetary form of credit (which I've called 'blue coins'). The purpose of this first system is to provide motivation for interaction (if a student collects blue coins then they can ask somebody else to do work for them i.e. spend their coins).
In addition to this form of economy (giving/receiving blue coins) I'd like to use the concept of 'gold coins': paid credit that can be used on professional services provided by teachers. This is the second system and is a marketplace of services.
Finally, I'd like students to be able to subscribe, either monthly or yearly, to a 'Pro' account that will add benefits and also give them a certain amount of gold coins for free.
To me this seems like it could be a confusing system to the user. Is there a precedent for using this type of system or should I try and simplify it?
(BTW, the 'homework-helping' context is contrived and is only for illustrative purposes).