NOBodE,
I only came across that not too long ago. But i have also only started looking for cases too. Unfortunately for me, I am in Australia, and thus, the cheapest place for me to buy that is via ebay. I ended up bidding up to AUD90. Which was still about AUD20 cheaper than getting it from lifeproof themselves, as the delivery would have cost me almost $30 extra!
As for the phone iself, i am planning to get mine from Kogan. It is an Australian online business that sells their products for Australians through a wholesaler in HK. With the exchange rates, and selling it directly to the consumer from HK, the customer dodges having to pay taxes as well, thus saving even more.
In Australia, the only place to buy outright is through Apple, at a cost of AUD799 for the 16G. At Kogan, so far including delivery, only 688. More than 100 saved. Only thing is the Australian adapter that comes with it, but i will just use my ipad charger instead.
As i am not a big phone user, my use will be minimal, so i will be using Amaysim for my prepaid provider. They have a "Pay as you go" rate, as well as an unlimited prepaid plan for Aud 39, i will be going for the previous. As you are in the US, i am afraid i cannot be of much help with your phone and carrier. But goodluck in finding a good one. You might also find this forum helpful. Whilst it is predominantly Austarlian, there are also some Americans On there too. Http://forums.whirpool.net.au and then go to thread search and enter your enquiry.
Good luck!