Regular price $0.00
Enter the amount you are willing to spend in the box that says "Pay What You Want", then click on the add to cart button, and you will be prompted to the checkout page that's on a secured network.  If you aren't directed to the checkout page after you clicked add to cart, then go to the top right corner and click the drop down menu that's represented in a yellow box with three white lines.  In there you will see at the bottom a link to take you to your cart and checkout.