Virgin Mobile does a mifi for $150 and an unlimited plan for $50 a month with no contract. Although they reserve the right to throttle speeds after you have downloaded 2.5GB. Actually, that's pretty reasonable.
"Unlimited" = 2.5GB? Okay, not entirely true since your speed is throttled after that but in my experience from Sweden is that "speed" is for mail and not much else.
So, all in all that doesn't sound reasonble at all. Am I missing something obvious here? (Honest question. I'm, always surprised how much you all need to pay for wireless over in the US.) Now, I say this sitting in Scandinavia where pricing on wireless data packages is relatively reasonble and a lot of people do have a 3G modem as their only connection (as am I with my 3GS tethered).
On the other hand I think we're worse off when it comes to finding wifi hotspots over here.
The total package I have is $50/month as well. I can use up half of that for calls/text. The rest goes to the data package, which is, in its current iteration, soft capped at 10GB/month (i.e. throttled after that).
Though, at the time I signed up there was no soft or hard cap so my data is truly unlimited (confirmed by my provider and my monthly downloads).
Sorry for going off topic.
I'm looking at getting the 11" MBA as my main and only computer and considering this and other threads on connectivity I can honestly say that the feature I want the most in the MBA is a built in wireless modem. I'm at a point where that is the only connection I'm truly interested in. Versatility over speed any day.