Ball python thermometer question!!!!!

Where can i purchase a thermometer for my ball python tank.I am looking for the one that can measure temperature, humidity, and I want it to have the probe (for exact readings) I have heard that it is possible to get them at walmart or similar type stores. Can anyone give me a more specific way of finding them ie, a name of the thermometer/hygrometer, what store, and possibly what section of the store. I have been looking online and found a few that may be what I'm looking for but I am confused because it says the product is for cooking use. PLZ HELP.! I feel as if my snakes tank is too cold. :snake::please::please::please::please::banana:

Hardware stores sell the indoor out door ones with the probe for around 13$ including tax :)

I use an acurite I picked up at lowes here and it is perfect.. the probe is over the heating pad under her hide and the unit is on the cool side. I think it was in the garden section but I just asked some one who worked there to help me find them lol

http://www.amazon.com/Chaney-Instrum.../dp/B001BO8CUE

Wal-mart carries them too... in their hardware section.