1. Make sure that popups are not blocked in the browser that you are using, as the PayPal website will attempt to open in a new window.
2. Wait a few moments after you click the "Purchase" button, as it sometimes takes a little while for the PayPal website popup to load.
3. Make sure that the PayPal window is not opening behind your current window. Try minimizing your current browser window to make sure that the PayPal website popup is not hiding behind it, which sometimes happens.
If all else fails, try using a different web browser (just to complete the checkout process).
This will almost always solve the problem. We've found that Firefox has the most problems with checking out, and recommend using Google Chrome. If you don't have another web browser installed, you can download one for free here.
Just log in to PixelScrapper.com using the new browser, and visit https://www.pixelscrapper.com/subscribe to try checking out again.