Exam site with access management to quizes

Hello,

I’m planning to build a website where i can create many exams, and in this site user can access exams based on their points, and collecting those point will be done by letting each user to get a specific numbers and when he enter those numbers into his account it will credited with 30 points and this points will be used to access the exams.

so far i found a nice plugin for the exams and another one for the access manager but I stuck on trying to fit in the points methods. since i have a list of serial numbers and user should use only one number out of this numbers to charge or credit their account with points.

can someone please advice me our guide me on how to achieve this.

Thanks
Almajed