This is not eBay, or minibike parts, but still a deal imo.
These little flashlights use one AAA battery (not included)
They are small and light and impressively bright. They are great to carry in your shirt pocket. You can spin the pocket clip, carefully, and they will clip on to the brim of your hat...headlight. They seem to be tough enough, although I've only been using mine for a few months...but I use them pretty often. It takes a few weeks to get them from China, but they are well worth 5 bucks. I've bought 12 now, and I've given about 6 or 8 away to my co-workers and friends.
https://smile.amazon.com/gp/aw/d/B01C77ULYI?psc=1&ref=yo_pop_mb_pd_title