Portable humidity tester?

It says inquiries go here...

I'm looking to house several scorpions in different tanks, but purchasing a humidity gauges for each one might get a bit pricey. Is there something that can be used to check each tank like once a day?

I use one of these hygrometers mate, may not be 100% accurate but they're not exactly expensive and give you a good enough idea of the humidity.

http://www.exo-terra.com/en/products/digital_hygrometer.php

I've never used a humidity gauge and I've been keeping stuff for almost 7 years man. Just check to see if the substrate's moist or dry. More ventilation = less humidity. You can also kinda tell with your hand or finger if it's humid inside a container. Of course, if you want to be just 100% sure, a hygrometer would definitely work lol