Buffalo Trace and Bulleit, both mentioned, are the best bourbons I know of for the price. They're both under $30 where I am, usually $25 and $27 respectively. This is perfect for me, since I tend to shy away from any bourbons costing more in favor of a similarly priced Scotch or Irish (though I will say that Woodford and Knob Creek are my favorites).
Also, I have to throw a good word in for whisky stones. I like my whiskey neat in a freshly rinsed glass, and these help on a really hot night. I'd say they're intended for thsoe who prefer neat-they just take the edge off a bit. The whiskey is cool, not cold, like it would be if you were drinking it outside on a 65 degree night.