The first criteria should be: Does it make you say "hell yeah!" Whenever you look at it?
Any gun made since the 50's will likely shoot well enough to hunt. Any gun made after the 80's will likely be easy to scope.
Also get a .308, .30-06 or .270. We are in a recession, stores are closing left and right. Your boutique caliber will be in stock once every five years, maybe, for the price of a nice bicycle. You will need that bike to go to work.
Try to buy a nice quality, low magnification optic. Avoid vortex unless you are white trash, like me.
Also get heated soles and a heated vest for any amount of still hunting. Best 500$ you will spend.
Try not to shoot your #### off.
Camo is mostly unnecessary. Buy hella blaze orange clothing. Wool is king.
Carry a big knoife. You will feel cool. Then carry a smaller, folding knife when you get lazy and jaded
Bring a good book to the blind. Or bring a comic book if you are like me.