The most low-budget yet effective option is a rubber hot-water bottle, which can conform to any part of the body and never needs to be turned off. It does lose heat over time, however. So if you need prolonged heat or don't want to deal with heating water, a wallet-friendly electric heating pad is a better choice. There are only three features it needs, which are standard to most pads in the $15 price ranges, says Roger Herr, a Seattle-based spokesperson for the American Physical Therapy Association: a size big enough to heat your back but small enough to wrap around an ankle; a soft cotton cover, so skin doesn't get burned or irritated; and at least two temperature settings. Why two? Smaller areas of the body, like your hands, feet, and head, can tolerate higher temperatures for longer than larger areas of the body, which need a lower heat setting. Pricier pads with extras such as moist heat don't offer added benefits, so they're generally not worth the expense.