My buddy says Ancient Age is some of the best bourbon in its price range. I have no idea, but might try a bottle of 10 star 6y/o AA. I know its from the Buffalo Trace distillery and I know they make quality stuff. He says Benchmark is good too, and I like it mixed, but I rarely mix.
I will have a hard time finding a better bourbon than Very Old Barton in the price range, but I'm will to try in my endless pursuit of great bourbon at a fair price.