If you're a Prime member, Amazon are giving away free gift cards. They come in their own presentation cards too.
And they're free! What will you buy with yours? Probably nothing - because they come with nowt on them :)
Useful also as flash cards for learning the first letter of the alphabet, or as a windscreen ice scraper, or for... well, topping up and giving as gifts.
And yes, they deliver them next day by Prime delivery too...