In a time when so many things cost $19.99 that have never cost $19.99 before, I'm delighted to inform you that there are still tons of game-changing products available for less than $15 if you know where to look. Whether you need a fix for oily skin, a way to stop your bedsheet from constantly sliding off, an ice tray that won't spill, or an easy way to clean your cast-iron skillet, these 31 products will make you think, "Where have you been all my life?!" the second you use them.