Member / Credit System Script

Hi everyone I am looking for a programmer who could help me with a simple member / credit system script. I have a local mysql database, which visitors can search on my site. I need a member / credit system script where visitors can sign up for a member account and then buy credits, which will be required to search my database. Visitors must be able to see how many credits they have remaining everytime they search the database. One credit = one search on the database, and I am looking to charge $1.50 per credit. Visitors can then pay by means of Paypal or direct bank depost. Only me as Admin can add the credits once I receve the payment. I am looking to spend around $50 - $100 on the script. Please let me know if you can do this. Thanks Sam