Glow dots, or phosphorescent dots, or gun sight dots, whatever one wants to call them, they are indeed a popular choice amongst gun enthusiast.
Some manufacturer offers a few of them for about ten bucks. A bit pricey I think.
Here is an affordable alternative, Glow-On purchase option 2:
The improved self adhesive material charges in a couple of seconds and the afterglow is very bright.
All you need is a hole punch and you can make not ten, but hundreds of glow-dots for all your guns and have extra dots for all your friends, all for just a few bucks.
A couple of notes:
In the world of afterglow material, bigger is better, all the time, so go ahead and create over sized dots, they perform better.
The adhesive part will work flawlessly for bigger applications like flashlights, gun mags, light switches etc. On small size dots is better to rub off the adhesive with a paper towel and alcohol and use super glue "GEL" (the gel type gives you a couple of extra seconds to situate the dos exactly where you want them).
Easy does it and here is a video to prove it: