The last time they had this offer, it was restricted to only electronics and toys. But it looks like today you can use this on anything that Amazon is selling (must be thru Amazon directly, not a third party).
The additional $10 off credit will be emailed to you within a few days. It’s good only when you spend at least $50 and also, you must pay using your Mastercard.
Have fun shopping (and yes, I will have a few other great Amazon deals for you to add to your cart later this evening – if you’re looking!)