Changing plans

Switch carriers?

There is no fee to switch within the same carrier.  All carriers have activation fees for new accounts.  

 This is why carriers offer credit for switching if you keep your bill current.  Please note, if you don't pay the first couple of bills on time you don't get the credits, which are substantial enough to have no bill for a couple of months once issued.

Well yeah, did you think it was free?

the first line is $100.  The rest are $40. The 4th line (free) will be credited after 3 months. 

The plan was well advertised.  Didn't you ask what the cost was?

https://www.att.com/shop/wireless/unlimited-plan.html

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@Nicole1206 wrote:
Yes, same carrier. I was on a mobile share and switched to unlimited. Charged a fee per line and they aren't even the same price. I'll call them in a little while.

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There are no fees to switch from mobile share to the unlimited plan. The plans don't have the same price but there are no fees. Most likely what you are seeing are pro-rated charges for all the changes.