This is a fairly common issue when people are integrating with third party payment providers: - http://checkout.google.com/support/sell/bin/answer.py?answer=88

This is a fairly common issue when people are integrating with third party payment providers: - http://checkout.google.com/support/sell/bin/answer.py?answer=88180 http://checkout.google.com/support/sell/bin/answer.py?answer... - https://payments.amazon.com/sdui/sdui/helpTab/Amazon-Simple-Pay/Amazon-Simple-Pay-FAQ#malicious https://payments.amazon.com/sdui/sdui/helpTab/Amazon-Simple-... - http://letsearndollar.blogspot.com/2009/07/change-any-paypal-price-with-data.html http://letsearndollar.blogspot.com/2009/07/change-any-paypal...