Our phone company will install "extensions" of the house phone if the buildings are within a certain distance.
We have always had our farm shop on an extension.
Then if the main number rings, we can pick it up at the shop.
when my dad passed away, I wanted to put the shop as an extension of my house. But my house was a quarter of a mile up the road, so no go.
So, I put in a complete separate number for the shop. Till I got the bill. Bill itself was fine. The charge for the phone service was around $18. (6 years ago). But the fees, taxes, Federal taxes, Al Gores tax to give poor people internet service, End use service charge, etc. added up to more than the cost of the service.
I kid you not. Taxes and fees were more than the service for the phone. I sent a copy of the bill to my congressman and sent a letter. then dropped the phone.