iPad Hardware FAQ: if I wait and pay more for the 3G model, do I get free 3G access?

If I wait and pay more for the 3G model, I get free 3G access, right?
No, the extra cost is ostensibly to cover the extra hardware required for 3G connectivity. Cellular data will cost extra.

How much extra does the 3G access will it cost in the United States?
Apple has struck a deal with AT&T that lets you pay either $15 a month for 250MB of data, or $30 a month for unlimited data. But unlike with the iPhone, a 3G plan isn’t mandatory, and there’s no contract involved—it’s pre-paid and on a month-to-month basis. So you could, say, activate 3G service for your iPad before your vacation and pay just for that month. The iPad will even let you set the plan to auto-cancel at the end of the month, so if you forget you won’t be charged any extra.

What about if I already have a data plan for my iPhone. Does that count?
Nope. Each device requires its own plan.
In the United States, AT&T doesn’t have good 3G coverage where I live, work, and travel—will it work with Verizon or T-Mobile instead?
Not at the moment. Although the 3G-enabled iPad will ship unlocked—meaning it won’t be tied to a particular network—the device uses a GSM chip that’s incompatible with Verizon’s 3G network. T-Mobile is a GSM network, but its 3G data runs at 1700MHz; the iPhone’s 3G components support 850, 900, 1800, and 1900 MHz GSM/EDGE, and 850, 1900, and 2100 MHz UMTS/HSDPA. Bottom line: the iPad won’t work on T-Mobile.
Beyond that limitation, the 3G-enabled iPad requires a micro-SIM card for mobile-network access; currently, AT&T is the only U.S. carrier using these cards. (Other international carriers also use mini-SIM cards).
If you want to use an iPad with another cellular network, your best bet is to just buy the Wi-Fi version and a Wi-Fi-based cellular modem, like the Novatel Wireless MiFi. You’ll have to pay for a plan, but you can use that wireless connection with your laptop, iPad, or any other Wi-Fi-capable device.