I've been recently looking into traveling to ATL as a single (flights from CT to ATL (with a quick stop in FL for a few days as well)
& prices are kind of steep(ish) but not horrible - yet. (A little under 500 bucks for a multi city flight out of a small(er) airport to begin with (CT).
If you don't mind layovers with flights, prices go down of course.
Anyways, that said, here is the info that
FIRST has about team bookings:
http://www.usfirst.org/community/frc....aspx?id=11290
You'll want airfare, a hotel, & more than likely a MARTA (public transportation) pass for your days there (depending on where you stay).
The airport is about a half hour ride to the GA Dome (via The MARTA) & if you stay near the airport, your hotel rates are cheaper but you have a commute in & out every day (by MARTA).
Staying near the GA Dome is easier but more expensive for the hotel fee (but you may only need 2 rides on the MARTA (back & forth from airport to hotel on the day you arrive & the day you leave) so you can skip the multi-day MARTA pass).
It's all about how much your budget allows, & how much convenience you want in the mornings (and nights) of competition.
Do you want to walk right from your hotel to the venue, or can you tolerate a morning & evening train ride of about a half hour (or less) to get back to your hotel?
Let us know how you make out, & good luck!