I have an unlocked Android (G1) phone. Miranda would like an iPhone, so we've decided to switch to AT&T. She can get her iPhone and I'll put a SIM card into my Android phone. (I'm okay with 3G not working on the Android.)

My initial thought was to get a free phone from AT&T, But then it occurred to me that this would use up my phone subsidy for two years. I tried adding a second line to a family plan on AT&T's website and then removing the phone, but it wouldn't let me complete the order. I decided to chat with their customer support. Here's the conversation I just had with them:

▶Thank you for your patience! An AT&T sales representative will be with you shortly.
▶You are now chatting with Tiffany, an AT&T sales representative.
Tiffany: Hello, Laurence.
Tiffany: Welcome to AT&T online Sales support. How may I assist you with placing your order today?
Laurence: I want to get a family plan with 2 lines, but only want one phone, as I already have an unlocked GSM phone that I would like to use.
Laurence: Is there a way to do that?
Tiffany: I will be glad to assist you.
Tiffany: You may order a free phone so that you can get the SIM Card from that phone.
Laurence: Im thinking about if the phone I'm using breaks or something, I'd probably rather get a better phone than just using the free phone. By getting the free phone I'm essentially locking myself out of a subsidized phone for 2 years though, right?
Laurence: (It also seems like a waste to get a phone I'll never actually use.)
Tiffany: If you would like, you may purchase a SIM Card in the store for $25, but once you sign the contract, it will be 2 years before a upgrade discount is given.
Laurence: I have to wait 2 years to get a subsidized phone even if I don't get any phone to begin with?
Tiffany: Yes, since the terms are for two years.
Laurence: So there isn't any way to get the contract, but hold off on getting a phone until later unless I want to either wait 2 years, or pay the full, unsubsidized, price?
Tiffany: You may set the line up online as a individual plan, then when the phone arrives, you may merge the lines in the store as a family plan and inquire on later getting a phone at a discounted price if you are not purchasing a phone at the time.
Laurence: I'm a bit confused.
Laurence: Let's pretend I was just getting an individual plan.
Laurence: Is there a way I could get an individual plan with just a SIM card (no phone), and then a few months later get a phone at the same price as if I'd gotten it when I got the plan?
Tiffany: The SIM Card will provide you with service, the service is for two years, it is not necessarily the phone, it is the contract that you are agreeing to which determines your discounts on the phones.
Tiffany: You term will still be 2 years, making it that amount of time to upgrade to a new phone for a discount.
Laurence: I understand that. I'm just surprised that I have to use the discount at the beginning of the contract or I lose it.
Tiffany: I do understand.
Tiffany: I do recommend that you visit your local AT&T Store to inquire on the procedure of using it at a later time.
Laurence: Ok, I'll try that. Thanks.
Tiffany: It was my pleasure, may I be of further assistance today?
Laurence: No, that's all I wanted to ask about.

The part that's especially ridiculous to me is that AT&T is essentially forcing me to waste their money. If they would let me save my subsidized phone discount for later, chances are I wouldn't even use it. Instead they're telling me I have to use it now, which means I definitely will and on a phone that I'm not even going to use. I don't even want to think about what that $25 charge for a SIM card that Tiffany mentioned is about.