I am just trying to deal with a rather small budget.
I understand that and if it is the case you would be better of with a dimmer switch http://www.lowes.com/lowes/lkn?actio...-WH&lpage=none to temporarily control your temps until you can invest in a more reliable thermostat.
Now, it says it requires wiring (or pay $15 extra to have it wired for you, which I would rather not do.) Do you happen to know if this is difficult or what exactly is involved in wiring it?
It's not that hard but if you are not confident enough to do it yourself you should have it wired.

Trust me it is a good investment, much better than the one that you are thinking about buying.

I have several of those and they are VERY reliable.