I know this has been brought up several of times since I've been a member here and nothing has really sparked my interest, until now.  I ordered 3 sensors and a tag manager from Wireless Tags and couldn't be more happier.  Super simple to setup via smartphone app and now I can monitor my stashes humidity and temperature and also create custom alerts for same.  They also offer a motion sensor in case you fear someone getting into your stash.  A buddy of mine from another forum introduced me to them so please use his link if you plan on ordering.  Also I would recommend emailing the company and asking if they have any promotional deals as I received a 15% coupon code.  Below is a screenshot of what the app and sensors show from the home screen...way more detailed when you actually click on the sensor.  For the 3 sensors and tag manager it was roughly $107 shipped.  Can't be beat and couldn't be happier after a long hunt.  Furthermore they don't just work locally when you are in your house on your own wife they work anywhere your phone has internet.  Any questions let me know...