I’m looking to buy a moisture meter for chasing down leaks in my motor home (RV).  I’m not looking to break the bank.  Just want something that will work reasonably well and I don’t mind poking a few small holes in the vinyl wallpaper to check behind for moisture.  I see prices from $29.95 to $350.00 for a non-invasive type with all kinds of bells and whistles.  Anyone had any experience with one?  What have you used?  What should I look for?