Codeigniter Paypal IPN Integration

I am seeking a freelancer experienced with PHP, the Codeigniter MVC framework, and the Paypal API/IPN, for a low-budget integration project. The project is fairly simple and based on a website which offers premium membership subscriptions. The final product (probably just a library file) must have the ability to detect successful Paypal subscriptions and update the user's MySQL database information accordingly. The product should also detect changes in the Paypal subscription (such as cancellations) and be able to update the MySQL database... changing the user from premium to standard. Again, this project is very low-budget, and therefore cannot go any longer than 4 hours. If-- at 4 hours-- the freelancer does not have a final product, freelancer may keep his/her work and will not receive monetary compensation. APPLICATION SETUP INFO: Codeigniter 2.1 Database Class: Active Record Paypal Payment Solution: Paypal Payments Standard