If having all the networks is important to you, you might want to look into
Aereo, particularly if you are going to buy a Roku. It's not free but it only costs $8 or $12 a month, however you can get a free trial month to decide if it will work for you. It will let you watch and/or record TV from the Atlanta TV stations (Athens is included in the Atlanta area). It is entirely over the Internet, you don't need any TV antenna at all, and while you can watch programs on any computer with a web browser, using a supported TV box will let you watch on your TV. You might want to visit their site and explore their offerings. Note that you can get a free month of service to try them out, but if you know you are going to get a Roku I'd wait until you have that connected before you start the free month, unless you don't mind watching TV on a computer monitor.
The one caveat is that because of the technology they use (where each subscriber actually gets their own dedicated tiny TV antenna at Aereo), they say they do not have to pay the local TV stations retransmission fees like the cable companies do. As you might expect, the stations disagree, and the dispute is headed for the Supreme Court later this year. If Aereo loses, they may be forced to shut down their service, or pay those retransmission fees which would make their entire business model nonviable. Even though I am not an Aereo subscriber, I really hope Aereo wins, for a number of reasons you probably don't care about. Well, actually, there is one other caveat - you must have a reliable high-speed internet connection or Aereo either won't work at all, or the picture will be highly compressed (to the quality of standard definition or worse).
Because Aereo requires no antenna at your apartment you will not get into any hassle there (although I will point out that they can't legally forbid you from putting an antenna in an area that is exclusively under your control, such as a deck or patio attached to your apartment, if that's what you need for reliable TV reception. Of course if you do that and it bothers them sufficiently, they will probably start looking for any legal reason to evict you). And because the tiny antennas they use are probably located very close to the Atlanta TV transmitters, you will not have issues because of the distance between Atlanta and Athens. But as I mentioned, the drawback is it's not free like an antenna would be, but it's also not anywhere near the 80 bucks a month your cable company charges.