Why is this digital thermostat so cheap?

[Vypyrz]

My budget is between 70-80, maybe a 100, whats the best for that price range? (under 100)

i looked at thermo's on ebay but im completley lost on what i should be looking for, i keep getting alot of stuff that looks like it should be hooked up to a boiler for a school cafeteria or something.. any links to the ones you guys are using?

Here are some links you can use:

http://www.spyderrobotics.com/home/products.html

http://www.reptilebasics.com/thermostats

http://www.amazon.com/Hydrofarm-MTPR...1529683&sr=1-7

http://www.amazon.com/Zoo-Med-ReptiT...5950692&sr=1-1