For a starter tarp in the southeast, I would recommend a 8x10. I know some people use 6x10 tarps and even smaller but they have less margin for error and I think for just starting out having that extra margin is beneficial.
I think the only 8x10 that is under $80 new is the Equinox one. It might not be as nice as some of the others because it it uses grommets instead of tie outs, but I have a friend who has tons of nights under one of their 8x10's and hasn't had a single problem with the grommets yet.
I notice your avitar is at Stecoah Gap. Is isn't a huge climb, but I remember that climb going north being a killer at the end of a long day.