Hotels can be pretty expensive. Going rate seems to be around 150/n these days for the main nearby hotels. There is the Super 8 nearby which is a bit less but also not as nice of a place. Obviously, the more people you squish into a room, the cheaper it'll be. And sometimes people are looking for roommates if you're not a large party.
Personally, I've used Priceline the last two years and this year stayed at the Georgian Terrace for only $307.78 Wed to Sun (4 nights @ $65/d bid + Priceline fees). Even ended up with a 1 bd suite which I was not expecting (there was just my husband and I). We're not as close to the venue but it's not that bad of a walk and worth the savings to me. Plus we were really close to the Vortex which is a place you must check out if you're over 18 and especially if you're over 20. Only downside is that with the Name Your Own Price system, you're not choosing a hotel so it'll place you somewhere in the area that you select (you can choose Atlanta areas like downtown, midtown, Buckhead, etc - downtown being the one you want) at whatever star level you're looking for. There's a forum that helps give you an idea of what hotels you might get and what star levels and at what bids people have been winning. You're also completely locked into paying if the bid is accepted and will get charged right away. I've heard a lot of people bitch about this but it's not like that's part of the hidden contract info. They tell you up front.