No, it's not like a cell phone where you have to buy a data plan. You use WiFi (at home or at businesses such as McDonalds, Starbucks, etc) instead to connect to the Internet.
Advantages of Kindle Fire:
1. Its unique cloud-accelerated "split browser" is optimized for web browsing and multi-media, which are the best functions of tablets.
2. 7-inch display is very easy to handle and is highly portable.
3. Its $199 price is very low relative to other tablets.
Disadvantages of Kindle Fire:
1. No cameras; no SD cards.
2. 7-inch display shows smaller views of documents and movies than 10-inch displays do.
3. It's not running the latest version of Android.
It looks good overall, but it's up to you to weigh the relative importance of those factors.
Reasons to order a Kindle Fire now:
1. You'll be in line ahead of others should supply not meet demand.
2. You know you want it for sure and don't want to think about the decision any more.
Reasons to order a Kindle Fire after release:
1. Problems could manifest in the Kindle Fire once it starts shipping.
2. Another product might be released which you'd like more.
All things considered, given Amazon's excellent track record with Kindles, I don't think there's much risk in going ahead and pre-ordering the new Kindle Fire now.
Alternatives include the Nook Tablet ($249) and the Lenovo Ideapad A1 ($199).