I just use disposable. They last me a few weeks and cost less than a dollar per battery. I like the Duracell procell. Same as their more expensive consumer variant, just packaged different and almost half the cost.

https://www.amazon.com/Duracell-Procell-AA-Size-Pack/dp/B007681K6C/ref=mp_s_a_1_7?keywords=duracell+aa+batteries&qid=1566762854&s=gateway&sprefix=dura&sr=8-7