Cell phone signal booster

BLUF: Need a $100-200 booster on AT&T edge and 3G freq. Does not need to be mobile, 12v ideally instead of 110v AC.

I'm trying to find a good signal booster for my dad. He has a cabin in the woods that has sketchy at best signal (if he stands on a ladder outside the cabin he can set his phone down to recieve text messages). He uses AT&T and it's either edge or 3G signal that he gets (LTE won't be there for a while). What is the best option for a booster/repeater so he can talk clearly on edge/3G? Budget is within reason (100-200, no 1k booster).



Any input would be greatly appreciated.

How about a used satellite dish?

Well to be honest, I need a plug and play solution. My dad is looking for an excuse not to get one! My mom wants to have signal when she visits and I want one for safety (if my dad breaks his leg or has a heart attack, he won't be able to call).