Sounds great!  Can you have another add on,  and let users place ads/classifieds/list items or whatever which have a credit value.  Then when the item sells the credits get transferred from one user to the other.

Kind of like a Credit shop? Hmm I'm thinking something along the lines of the Gifts plugin, where users can pay credits to give other players gifts. Obviously not quite the same, but a similar idea where the transferring of virtual goods comes into play?

Yes exactly - A Credit Shop.  Users upload an image of an item and adds a description.   I think Admin needs to set the value of a credit.  e.g $1 =10 credits.  Users enter the value in real money which then gets displayed in credits. e.g $30 would be displayed as 300 credits.   Then these credits would get transferred.  Need to think about shipping costs too.

Hmmm, I think this is more of a separate plugin that would work with CreditsFree. I will look into developing something like this tomorrow morning :) Thanks for the suggestion, Jacq!

Plugins are packages of code that extend the core functionality of WordPress. WordPress plugins are made up of PHP code and can include other assets such as images, CSS, and JavaScript. By making your own plugin you are extending WordPress, i.e. building additional functionality on top of what WordPress already offers. For the more info visit: Ecommerce Marketing Agency