Help a greenhorn make the move to an iPhone 4? | Phone/Device Issues and Features | Consumer forum

I know this has been talked about, and I've tried going over old posts, but they're scattered far and wide -- I'm a bit uncertain and would really like a good summary of what to look for and what questions to ask, as the iPhone 4 is a big investment.

So, this is what I understand I need to do. Can anyone confirm that I've got it right, or fill in details where needed?
1) Find a used phone that is either on a Rogers plan, or is "unlocked".
2) Cut the SIM that I currently have in my Nokia 1661 into a micro-sim size.
3) Follow the registration process that I've seen posted about on this forum.
4) Sign up for $10 data plan if I want to be able to browse/check email when not in wi-fi areas.
Is there anything else that I should be aware of before embarking on this adventure?

Oh, and can anyone tell me what a fair/decent price should be on a used 32G iPhone 4?

thanks in advance!
mms