Quite often, when buying books off Amazon, you can sometimes get them cheaper by going to a marketplace seller’s own website. That’s how I came across The Book Depository, where I have bought a few books recently.
One nice UX feature that I like on this site was the way in which they highlight where to find your credit card CVV/security number depending on which credit card you are using:
The image above shows the security number highlighted on the signature strip when you select Visa from the credit card type drop-down list. Compare that with the screenshot below showing the security number highlighted on the front of the card when American Express is selected:
It’s a simple feature really, but nicely implemented.