I actually recommend several in that price range. There is no one "best" or even a "best for you" as some would suggest, because every binocular is a compromise of some sort. I have learned what is important to me in a binocular, and what is less important and that helps guide my choices. Image quality is important, no doubt, but if it comes in a package that gets on your nerves for one reason or another, then it's hard to enjoy the image quality.
Solid recommendations in that sub-$500 range are the Nikon Monarch 7, Vortex Viper HD (now assembled in the Phillipines instead of China), Maven C1, Opticron Countryman, and Vanguard Endeavor IV.
There are quite a few in that price range that I've owned and returned, but the list above is a group of bins I can recommend without hesitation. There are differences among them, but all of them have earned a great reputation and don't have any "weird" stuff going on that would cause someone to just return them outright.
Now, if you're talking used, then that opens things up a little more too. You can generally find some Swaro SLC 8x30's, Meostars and possibly even a Conquest HD or Trinovid for $500 if the seller has a weak moment.