We rely on AC units and fans whilst indoors, but for those wanting to be outside or on the go, a USB fan is a must. These rechargeable, portable fans are ideal for camping, barbecues, RVing, or beach days. Instead of relying on wires, these fans use rechargeable batteries and can run for well over 24 hours. These USB fans are all portable, however you should consider what you plan to use them for: wearable neck fans and handheld options are great for personal use, but won’t cut it if you’re in need of a desk fan. We rounded up the best USB fans to keep cool this summer and, best of all, they’re all under $40—a small investment that goes a long way.