Competition in the smallest MP3 player market is fierce with the likes of the shuffle and the Mobiblu offerings, so how about the thinnest? That’s what you get with the Walletex MP3 player. It’s just slightly thicker than a credit card, has all the controls you need to play music and will be available in capacities ranging from 128MB to 2GB. And if you’re a business wanting to show off, you can have them custom-made with your corporate design.