I'm trying to see if the broadband service that you have listed starting at $14.95 is for service for home computers or can you use it for Internet service anywhere you go?
I believe your question is referring to the Xanadoo prepaid mobile Internet service. Their service is actually the only one on the Prepaid Wireless Broadband Plans page that is a desktop modem.
In other words, while it's mobile in that you can take the modem with you, and you aren't tied to using it with any particular computer at any particular address, it's not truly mobile like the other USB prepaid modems and PC card modems are.
So while you may not mind moving the desktop modem for a weeks at a time, or a few days at a time between two locations, you definitely won't want to take it with you on a daily basis, and use it in your car, library, etc.