Hi, I'm visiting LA this may and I've some questions about the costs of prepaid dataplans to use in my 3G iPad, we got prepaid data for 1 day (1GB: 4 dollar, 1 week 3GB: 10 dollar or 1 month 5GB: 25 dollar)in Sweden, does something similar exist in the us ? What prices is to expect and where to buy it ? Thanks