If you’re doing the typical household batteries like AA/AAA, then you can get a pretty cheap kind like this one Amazon link for this specific one a.co/d/hrW6U45

I got one off Temu for less than a $1 and I use it all the time. Its only power source, as far as I can tell, is the battery, itself to move the needle. So if it doesn’t show a result, then it is a dead battery.