off contract purchase
This is what I'm currently doing. There are several internet GSM retailers that sell unlocked phones. You will need to do your research as there are a few 920's with varying frequencies. T-Mo is using the 1700, AT&T another. MVNO's are smaller affiliated service suppliers who resell AT&T lines at much cheaper prices. Examples of this would be Boost, Straight Talk, etc.
I googled top 10 prepaid cell services. That way I could compare their terms and rates across a single page, in addition to having the retailer website there if I chose to check further.
You also need to check your area for which carrier provides the best coverage. T-Mo has a great plan for smartphones, but the coverage in my location is below average right now. I found that AT&T has the best coverage for my needs. I did, however, decide to preorder a 920 that would work with T-Mo should their coverage here increase.
The next thing to check are the provider's sites for prepaid plans, once you have your top choices narrowed down. For example, I know I'll be using AT&T, at least at first, but not on their contract. They have another plan called GoPhone. I went to Amazon and purchased a microsim for AT&T. When I get my phone I'll put in the card to be able to activate my phone. I'll choose the unlimited everything plan, including data, for $65 a month, and I'll sign up for autorefill.
The nice thing about doing this is I'll use Googlephone for all my voice and texting needs. I have a number there that I'll give out as my number, and googlephone will allow me to forward that number to my 920. If I become unhappy with my service, I simply change carriers and get a new microsim. Then I just have to forward Googlephone to the new sim without having to make friends learn a new number.
Here are the websites I used. I preordered from
New Negri Electronics - Your Trusted Source for High End Unlocked Wireless
GSM Nation | Unlocked and Contract-Free iPhone, Android, and Blackberry cell phones lists the compatability of the phone with your country's providers
I used
AT&T, Verizon, Sprint , T-mobile New , Refurbished and Used Cell Phones; No Contract Cell Phone Plans, Flash and Unlock Cell Phone - www.beigephone.com - Everything cellphone. for cell provider information and googled "top 10 prepaid plan cell providers"
I also went to AT&T and T-Mo's websites for coverage and plan breakdowns, as well as Nokia.com's site for phone info and specs.
I wouldn't buy from AT&T because it'll be loaded with their crap and I didn't want that. I wanted a few more options as far as apps and providers goes.
I know this is long winded, but the benefits, for me at least, outweigh the cons when it comes to prepaid. I like the idea of no contract and choosing my own provider. Plus it should be half the price at least of my old Verizon contract!