If you want an iPad with 3G but don’t want to pay the extra money then you can tether it to your iPhone and use your iPhone’s unlimited data plan. The app to do this is MyWi and allows you to use your iPhone as a 3G modem for your iPad.
If you hadn’t guessed by now, this only works on Jailbroken iPhones so there is a risk involved. The app costs $10 and comes with a 10 day free trial.
(Please note prices are subject to change and the listed price is correct to the best of our knowledge at the time of posting)