You will really be surprised about the many times that a volt meter comes in handy. check, bulbs, batteries (large and small), check fixtures, fuses, campground pedestal voltage (then you/'me' see that someone turned off the power breaker
) (I "Fixed" the no power problem, honey,
)water heater elements.....etc, Keep it with the tools that you take camping with you.
Yes, you can get a cheap/free with a coupon from Harbor Freight, but get one that is one step above the type in quality they 'give away'. Not the best or even marginal, but does work most of the time. I got three different ones for free for 'grins'.... broke two and never took the other out of the package...