Hello,
I've been able to turn up a lot of data for the UK and EU. If you post a link please be certain it's applicable to the US. Thanks!

I've been looking to get a USB dongle and a SIM card for some time. I've gone into the stores and read the plans on prepaid cards and they all say "for cell phone only". I've searched the internet for hours and can't find a single thing on this topic. Not even a decent tutorial aside from the "You need a SIM card and dongle" type.
I know that I need a dongle and a SIM card! I know I can choose any dongle I want but might have to have a certain SIM card depending on what network I sign up to.
I can't find any information on which SIM card I need and plans for computers. I don't want much data, 100MB would be enough. I want to experiment a bunch with my PC and a hacker board like an arduino (which uses a 2G instead of 4G connection, but that's plenty fast for a the hacker board). I would need a network that could go faster for the PC of course.
I do want a prepaid card that will not expire any time soon.
I don't even need nation wide coverage, just Florida USA.

Any thoughts, ideas?
Thanks!

Since no one has replied... Maybe Verizon? They have prepaid cards that are good for mobile hotspots which might also work with USB MODEMS. You might have to visit one of their stores but may not be all that helpful if asking questions about the Arduino GSM Shield.

Look for tablet plans.

It is not easy to find data only plans here in the us, most just get a wireless/cell AP at wally world. Yrs ago I used a plan from clear with a puck and it worked well for data only but they diapered.

I guess I'll have to ask the carriers then.
Thanks, guys.