We use a few of these for something we don't mind bumping around in our field kits:

https://www.amazon.com/gp/product/B077FTPT46/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Not the highest quality, but mostly we use it to check signal on installs rather than the calibrated ones we use for more precise signal correction etc.