Assoiciate paypal payments with the payer

Question

So in my website I have in-game features which you can buy I have a miniature store made and paypal buy now buttons included What is the best and most secure way of automatically giving users there in-game bonus. When they have paid through paypal you have an option to put in a link when the payment is successful and i could have a form so when they are on that link it adds there bonuses but it also means anyone could just go to that link and get the bonuses for free.

Answer 1

A couple of options (this sounds like Payments Basic)

1. Have them enter their PayPal account email address into their game account profile. When you get your IPN you match those up and issue the bonus
2. Add the custom field to your HTML buttons . Associate that value to their user profile in your database. When you get your IPN, match the custom field up and issue the bonus