I am looking to add a shotgun mic but right now really cant spend over $500.00 can you recomend any?

The AT 897 mic is one of the most common lower-budget choices. The ME66 is another option. Rode has a couple in the price range you're looking at.
I'm a fan of the way the AT sounds, even though it's not the hottest mic of the three I'm recommending, it has the smoothest and most natural sound.