The TRX All-in-One Suspension Training System ($150) is the most expensive item on our list, but according to two fitness experts, it's worth it. "It is basically an entire home gym," said NASM-certified trainer Phil Catudal, who recommended it for its versatility and portability. "If you have a door that can support weight," said Amanda Murdock, director of fitness at Daily Burn, "then this is the one piece of equipment that I would highly recommend to give you a full-body workout." For upper body, she recommended using the strong, flexible bands for push-ups and rows; for the lower body, try jump squats, deadlifts, and glute bridges; and for core, mountain climbers and pikes.