How much is a T - 1000 Tempreture controller teminator

[25518]

I recently discoverd that a batch of beer I brewed, fremented & bottled tasted of apples. I couldn't figure out why until John Palmer's book. So me questions. How much is a temp contoller?
Even as I ferment a stout, should I still worry about internal temp in the wort? It is hard controlling the temp right now. About 75° as I just discoverd me stout is a cool 64 -66° as it is 78° in my house. So maybe worry about high temp. But, still need a steady temp.

 

[jungatheart]

This one's all put together but you can buy a do it yourself one for about $20.

http://www.amazon.com/Johnson-Controls-Digital-Thermostat-Control/dp/B00368D6JA/ref=sr_1_1?ie=UTF8&qid=1370646504&sr=8-1&keywords=johnson+controller