new funtionality add-website

I'm working on a project at the moment that each user has a 'credit-balance' this is kept track of via mysql. What im wanting is a payment system that the users pay into a paypal account then the amount they paid gets added to the mysql balance column of the user. Iv decided to work with 'Website Payments Standard' for now as the projects budget can not afford pro. but later on will be upgrading. Basically what i'm wanting is a Codeigniter based system that has a form input that users can type in an amount (that they want to deposit) minimum of $10 maximum of $1000 (i will need to change these variables from time to time) then they click 'top-up' which will take them to the PayPal purchasing site(I would prefer this being all onsite rather than going to PayPal but it seems this is my only option for now) then once transaction is complete PayPal will send information to a url that will pickup transaction data and check to see weather or not the payment was successful then add the amount that was paid into the users 'balance' column and also add all transactional details to transactions table along with the users id. ## Deliverables 1) All deliverables will be considered "work made for hire" under U.S. Copyright law. Employer will receive exclusive and complete copyrights to all work purchased. (No 3rd party components unless all copyright ramifications are explained AND AGREED TO by the employer on the site per the worker's Worker Legal Agreement). ## Platform website making