Are armbands similar to wristbands? How about exploiting current trends and making armbands suited for that. For instance, when the Ice bucket challenge, people were starting to learn about this medical condition called ALS. So at that point, you could sell bands with messages like 'Support for ALS' - you can be more genuine by contributing a portion of your earnings to an ALS charity.
Similarly, find a trend that is running now, and sell bands that stick to the trend. And if it is a 'I support' sort of thingy, be sure to share a percent to charity. It's good karma in the larger scheme of things as well as helps marketing your business as well.