How do I set up a prepaid token based system?

I am setting up a section of a website where employers can post job vacancies, but in order to do so, I want them to buy a token or number of tokens to activate the ability to post a vacancy. So if an employer has bought five tokens, and they post a vacancy, it will leave four remaining tokens for them to use.

Currently, I have a table for users (based on the double opt in tutorial), and I also have a table for vacancies listed.

I can't quite see how to implement this token system and need a bit of guidance on how to do so. Once I have an idea of how to go about implementing this, I should be OK with building it and the finer details, but I am at a loss of where to begin. So any advice you could give would be appreciated

My intention is to use databridge which I am well versed in, but this will be the first time I have used eCart. I'll use paypal as a payment gateway in order for them to buy the tokens. I get that you can use eCart to register products purchased, and by which user, but I just can't get my head around how to use a token system and recognise if a token for that user firstly exists, and secondly recognise that a token has just been used to post a job and there is now one less token.

What are you thoughts? How would you tackle this?

Thanks.

within ecart, in the checkout wizard is an option to save order information to the database.

you will need to use this option to save the order and order details information.

also, you will want to password protect the checkout so that the user has to log in before they can checkout.

Using the security assist user authentication, when a user logs in, a session is saved with the users ID. you will want to edit the eCart Store Order Summary behavior so that the Users ID is saved to theorizers table on checkout after purchasing the tokens.

you can then use a recordset to lookup orders placed by that user to find the tokens quantity that they have purchased.

I would also set up another table to record the tokens used by that user.

you can then use another recordset to look up tokens used and compare that with the tokens purchased.