CricKet offers prepaid broadband...wirelessly...

CricKet is introducing prepaid mobile broadband effective very, very soon. Granted, Millenicom has had this option for a long time on Sprint's nationwide network...and they're now offering a $55-a-month option that's totally prepaid like CricKet (startup cost is a whopping $343)...but CricKet is much more well-known and accessible. $40 gets you a month of service, $60 plus a $25 activation fee gets you a USB tri-band broadband card. A Kyocera PC card (dual-band) is free. The service is focused on CricKet's low-income audience, who would use the service (which has a 5GB soft cap) along with a CricKet cell phone instead of DSL or cable. Personally, I'm not sure how well this would be an alternative to terrestrial broadband; DSL is cheaper and faster, while cable is just plain faster. But for places where DSL or cable (or both) won't go, or for people who want internet on their laptops (or sub-$500 netbooks) CricKet is a viable option for those in its coverage area.

UPDATE: According to the info copied from PC Magazine in this post CricKet's mobile broadband is unlimited except for VoIP (because CricKet makes their money on such things) and servers. Of course, "server" could mean any remotely-initiated upload of data such as remote desktop apps and most likely P2P. Also, CricKet's own website (at least for now) says in the plan details that, among other things, performance may be degraded if you transfer more than 5GB in any given month. So you can use this modem as a single-computer DSL-replacement (speeds are comparable to a low-tier package I suppose) but not to replace phone service (CricKet sells phones for that) and not to replace TV (ten hours of programming in a month would easily put you over the limit...heck, six hours of programming would do it).