Unfortunately, that little gadget that sounds too good to be true almost certainly is. When an unfamiliar company claims that their magical camera is more than 10 megapixels, that's because they're probably using a 3- or 4-megapixel sensor and interpolating the image. Interpolation is a fancy technical term for "making it bigger and uglier." The image you eventually get might technically be 12 megapixels, but it will look like absolute garbage.
Similarly, don't expect your video to look very pretty, either. At most you're going to get a 30fps VGA video, about the same as you'll find on almost any digital camera.
Finally, when they say their product is an MP3 player, they want you to think you're getting an iPod. In reality, you're getting a memory card reader with a headphone jack. Once again, it's a device that would otherwise cost maybe $100.
If you haven't heard of it, if we haven't reviewed it, and if it promises amazing features at a discount price, you're buying digital snake oil. Steer clear, and remember to do your research with us before you drop the cash.