In this day and age, a power bank is essential. Between Bluetooth headphones, wearables, phones, consoles, tablets, and who knows what else, your gear may need some charging more often than not. Head to Amazon and pick up this Portable Power Bank ORICO 20000mAh for just $9.34 with 93XKN5AV coupon code. This is the best price in the history of this item. It typically costs $17, and there are positive customer reviews so far.
This power bank can charge modern smartphones four or more times before recharging. There are handy LED lights to let you know how much life the bank has left, and two 2.4A USB-A ports are available to charge multiple devices at once. The power bank is equipped with safeguards against things like overheating and overloading, and the 18-month warranty includes your purchase. Another thing to note is that the power bank is brown, which may seem odd at first, but it will help you to distinguish between your gear and that of someone else.
Note that your own charging cables will need to be supplied. I strongly recommend the 3-in-1 option of Anker.