J.✰.
Yes. We have a metal home too. Went to Best Buy and bought a "cell phone booster" for $300. Basically there's a unit you mount outside (on a tree or pole) and run a cable from the unit into the house (we have a small hole in our house running the cord. It's temporary, as we don't even have walls up on that part of the house yet, but I'm sure there are instructions included with the booster that tell you how to make it work nicely in your house.)
btw - we have T-Mobile. I used to have to go outside to be able to talk on the phone. I could find a spot to set my phone and at least hear it ring or get a text message. But the booster allows me to walk thru the whole house and have a great signal.
added - we had Magic Jack. Worked fine when talking to people on landlines but we did NOT renew ours b/c when talking to people on cell phones, it was very difficult to hear them.