Last things first
Because I think this was what my dad wanted to know when he requested the details of my experience, I will first share what I had to do to make my newly purchased phone work once I received it. In theory, this should have been easy. The phone was already unlocked to work with any carrier and even already charged! I should have just been able to put my old SIM card in the new phone and begin making calls (this worked consistently when I kept switching back and forth between the iPhone 3G and the 3GS). Unfortunately, I hit a road block this time. Apparently, SIM cards come in too many sizes. I'd already learned this when I had to get a new SIM to switch from the iPhone 3G (standard SIM) to the iPhone 4 (Micro SIM). With the new Droid Mini, I had to downsize again to a Nano SIM. Which necessitated a visit to the AT&T store to get my SIM card replaced. Once that was done, it was smooth sailing. My new phone worked like a charm!
So the moral of that story is that actually getting a phone to work with your network is probably the easy part.
Now, let me give you some helpful pointers I learned along the way about the hard part: buying a phone in the first place. Then, because this turns out to be a lot to digest at once, I'll follow up with one last post on understanding the mysterious beast that is AT&T. Now let's get shopping!
Know what you want
For me, my priorities in getting a new phone shifted a lot over the month or so that I was searching for one. Originally I really just wanted a small Android phone that worked fast and had a good battery (preferably replaceable). Then I realized, I really needed a half-decent camera for those spontaneous Unfashion pics I might need to take at work. While shopping, I found a number of phones that take microSD storage cards, which I thought sounded like a nifty way to transfer music and files from my phone to the computer and other devices...until I realized that most of the SD cards are buried under batteries and back panels and aren't really intended to be swapped in and out all the time. So that went off my priority list again, and I settled for a phone with an average battery just because it was cheaper. But all that aside, whatever your priorities are, you can probably use phonearena.com to help you find them. This site has a detailed advanced search feature and a nifty tool that'll let you compare the actual sizes of different handsets. Their staff reviews are also really thorough, though reviews of old phones do not really reflect how they compare to modern phones. Once you know what it is you're looking for, it's time to consider the things you might not even know you're looking for.
Carrier-locked vs. Unlocked
Some phones can only be used with certain carriers. When you buy a phone directly from a carrier, it is usually locked to work on their network alone. For example, you cannot pop your AT&T SIM card into a T-Mobile phone and expect it to work unless the phone is unlocked first. Now, you can unlock almost any phone, sometimes for free, but usually for a cost that can vary quite wildly. So if you're shopping for a new phone, I recommend buying one that's either already unlocked (this is different from jailbroken, by the way) or is keyed to the carrier you are going to use. I hear that they have just passed some law that makes it legal (read: easier) to unlock your phone at any time, so if you're planning to sell your phone, I'd recommend getting it unlocked first, because that way you can sell it for more money, since there will be a higher demand for it!
CDMA vs. GSM
It's an alphabet soup out there in the phone-buying world, and the first acronyms you'll probably run accross are CDMA and GSM. Apparently, not only can phones be deliberately locked to a specific network, but different carriers use completely different technologies to provide cellular service. Carriers that take SIM cards use GSM bands, and carriers that don't take them use CDMA—or something like that. Some phones are set up for both services, but others are not. If you use a GSM carrier and buy a CDMA phone, you will not get far. In most listings on eBay (where I bought my phone), the band will be listed in the specifications, so pay close attention to that. Theoretically, you can also use specific band version numbers to find out whether your phone supports 3G or 4G data, but that wasn't a huge priority to me, so I didn't investigate it much.
So far so good? Here's just a little example to confuse you all over again. Verizon is traditionally a CDMA carrier, and AT&T is GSM. You would think this would mean that, as an AT&T customer, I should have steered clear of Verizon phones. However, being the renegade I am (or just the pennypincher who will take any risk to save a few bucks), I bought a Verizon phone, because the seller had stated clearly that it was unlocked and would work on AT&T's network. When I brought it to the AT&T store for activation, the salesman got a very worried expression on his face. But he installed the SIM card anyway, and, voila! It worked. This just goes to show you, nothing is for certain in this world!
Bad ESN or IMEI
Here come some more meaningless letters! I don't know what they stand for, but apparently if a person's phone is lost or stolen, or if it is linked to a contract that hasn't been paid, it can be reported by the carrier as having a bad ESN or IMEI, and it won't work. Not only that, but you could be potentially breaking the law by using it! If you see a phone for sale with any mention of a "Bad" ESN or IMEI in the listing, just keep on scrolling. I think it might be possible to get these phones to work outside of the US, but here in the States, it's better to be safe and legal than sorry.
Woohoo! You've just learned in 5 minutes what it took me several days of phone shopping to begin to understand. Now you should be ready to explore that handset market with confidence. And, if you aren't already comatose from information overload, stay tuned for my next post, which I hope will clarify some of the murky waters surrounding everyone's favorite carrier (or at least, the one I'm currently using, AT&T Wireless!)