In the below video I review three types of battery cases for your AAs, AAAs, and 9Vs. I use these for my speedlites and radio triggers and am partial to Enloop rechargeables.
I started with this brand, they are 6 for $10. They fit both AA and AAA and you can aim the + end at the charged or empty end. However the hinges and closure are super cheap plastic and on one of mine the closure broke off already.
This next Battery Case is $3 each and is certainly an upgrade from the above case. It closes far easier, but it still has a plastic hinge to eventually snap from use. But these are good and sealed if you drop them on wet or muddy ground.
Finally there are the Storacell AA 12 Pack. They’re just so cool. I like the bright colors and the fact that the batteries snap into place, either positive tip up (to indicate full charge) or positive tip down (spent!). They’d get pretty gunky if dropped into the mud, so these are best if you have them stored in a case on your job – or just don’t drop them in the mud. Anyway, these are by far my favorite of the three.