Cell service costs the same here in the US whether or not you have an unlocked phone so you're not paying anything extra for a subsidized phone. What you sacrifice is the freedom to switch carriers for free during the two year contract period but in reality that's a problem for very few people.
That's not necessarily true.
For some carriers you pay the subsidized rate regardless of whether you BYOP (bring your own phone) or buy a subsidized phone from the carrier.
On T-Mobile when they were doing both subsidized and unsubsidized phone plans at the same time there was actually a notable difference between the monthly rates. I believe T-Mobile have dropped all of their subsidized rates.
So when you buy a phone through T-Mobile you either pay full price of phone + plan. Or Monthly price of phone + plan.
So for example.
http://www.t-mobile.com/cell-phones/apple-iphone-5c.html
You either pay 528 for the phone up front plus whatever plan you choose. Or you pay 22 USD per month for 24 months plus whatever plan you choose. And obviously if you brought your own phone (a used T-Mobile phone for example) then you just pay the normal price per month.
Also because of that you can buy a T-Mobile phone and use it on any T-Mobile MVNO but not on another network without unlocking it. So you can buy a brand new iPhone or whatever that is locked to the T-Mobile network and use it on a 5 USD per month MVNO plan like what I have.
In past to get that same phone for 0 USD, your cell phone plan would be increased by that 22 USD per month, but after 2 years it wouldn't drop down. It would remain at the subsidized price.
AT&T makes things REALLY convoluted. All of their plans are subsidized for a 2 year contract. But if you buy a phone on a 12 month "upgrade" plan, then you pay an extra monthly fee that makes up for the extra 12 months. So for example, for the same iPhone 5C as T-Mobile. You either get the phone on a 2 year subsidized contract with 99.99 USD down. Or you get it on a AT&T Next plan at an additional 22 USD per month (for up to 20 months) in addition to your subsidized contract, but you have the option to upgrade your phone after 12 months (and not be charged for the extra 8 months). In other words that 22 USD per month is to cover the cost of the phone that isn't getting paid by the 12 additional months of subsized service that you won't have with that phone based on the standard 2 year subsidized price structure.
So if you don't trade your phone in after exactly 12 months, you'll end up paying significantly more for that iPhone 5C versus getting it on the 2 year contract and being stuck with it for 2 years (unless you pay early termination fees).
And best thing of all. If you don't upgrade at the 2 year mark, AT&T continues to get you for the subsidized phone rates. IE - you're still paying a monthly charge for your phone in addition to the monthy fee for the service.
Oh and if you could bring your own phone? You'd still be paying the subsidized monthly phone rate as if you had gotten a new phone on contract. As well, you can't use any AT&T new phone on an AT&T MVNO without unlocking it. And AT&T doesn't allow their new phones to be unlocked in the first 6-12 months usually.
Bleh.
Regards,
SB