Would a cell booster work?

[TrainChaser]

I am trying to reduce the cost of my landline phone + Internet ($108/mo).  Someone suggested T-Mobile, but when I checked their coverage map, it was medium coverage (outdoors & most homes).  But I live in a metal-wrapped mobile home.  I called the local T-M office and asked about it, and the guy said he has the same problem, the only place he can talk is on a tiny, glassed-in porch.  I don't have anything like that.

This place also has two large alumimum porches attached to the mobile home, and a solid steel wall on both ends, and has a hill between my house and one of the two local towers.  I have tried TracFone and got no signal at all.  I used someone's U.S. Cellular phone, and could only talk out in the middle of the back yard.

Would one of those cell booster units help me get a cell signal in the house in this predicament?