As much as we love the sound that good over-ear and on-ear headphones deliver, they're not always appropriate. Sometimes you want a pair of headphones a little more discreet and portable. That's where in-ear headphones. Different from earbuds, in-ear headphones crank out premium sound without making you look like you're on your way to DJ a party. While you can cop a pair for up to $500, there are a bunch of really good affordable options. If you're looking for a good set this holiday season, consider these 10 in-ear headphones under $100.