I use the wireless internet card from Verizon. As for speed, I get an average of about 33K. I pay $80/month. I hear that Verizon is going to be updating the service to broadband speeds in the near future while still only charging only $80/month.
The service is worth the price as it has come in very handy in the field for accessing MLS and on listing presentations. I get the most use out of it when I go door knocking while prospecting for listings. When I walk up to a home I can pull up the owner info, last sale price, and house dimensions from the town hall's online database.