Deals for adding a line without transferring number

Are there ever deals for phones when adding a line without transferring a number?

I have only been looking for a month, but have only seen deals when either transferring numbers or upgrading my current phone.

I can get the deal for upgrading a line, then I can add a line and bring my own phone (bringing my current phone), but that seems like a giant hassle.  And, I wind up with a new phone, and my son would get my old.

My son is getting his first phone, and I would not like to have to jump through hoops to get the same deal for adding a line as upgrading a line.  Thanks