I recently considered buying an iPad and discovered there are four different ways to buy it that result in a price difference of $330! The iPad is by no means a necessity, according to an Apple-obsessed friend of mine, but if you are going to buy one you might as well get a deal. See below for basic tech terms.
MiFi – A small device that allows you to set up a WiFi hot spot wherever you are.
3G – A high-speed Internet network that the 3G iPad can connect to (the WiFi iPad can only connect to WiFi hotspots, like at McDonalds, Starbucks, or your local library).
This chart assumes you do not break anything and incur replacement costs. Check warranties on all devices before you buy.