This hobby does have some extra costs, ya know.... batteries, eye protection, matches, balloons, etc
If you've spent the money on 8 lasers, you should have a battery budget too!
Before I buy any laser I do some research into what it takes to power it. Sometimes similar lasers from different manufacturers use different batteries, so if at all possible I buy lasers that use batteries I already have.
But overall it *IS* a pain in the ass that there are a LOT of different batteries used in these things... I got my first pointer that used CR2s and I had to hunt around to find a place that sold them.
And now I realize that if I want to use the pointer with any regularity, I should invest in rechargable CR2s... which means the batteries AND charger.
And, of course, the next pointer I get will probably use CR123A, which means ANOTHER charger....
Anyway, the point is if your're going to get into this hobby, an investment in batteries & chargers is just par for the course.