You can get this thermometer/hygrometer from Home Hardware, don't remember exact price but between $15-20.
http://www.homehardware.ca/en/rec/in...Ntt=hygrometer
Local store didn't have it in stock but I ordered online and it was delivered there within a few days.
and a Benetech IR temp gun,
http://www.dx.com/p/benetech-gm320-1...Q#.VG-jyovF-oQ
it's a good combo to have constant ambient readings in the tank and also take spot measurements of enclosure glass surface, thawed rats, etc. The temp gun is accurate when held about 2" - 6" away. Free shipping but it took around 3 weeks to arrive.