There are plenty of threads about "the best" sub-$300 scopes. And, after weeding out the cheap pretenders, any consensus about what's best usually boils down to two factors: what are you going to do with it, and personal preference.
For a particular scope recommendation, it might help to know what distances you would likely be shooting/hunting. I mounted a Burris E1 3-9x50 on my new R15. I plan on using it for predators within about 300 yards. The 50mm objective will help in low-light dusk/dawn hunting. If you're looking at taking shots significantly farther than 300 yards, I'd think you would want something with more magnification; less for a "woods/brush gun". And, if you won't be shooting at dusk/dawn, a smaller objective may be appropriate.
Right now, SWFA is selling the Zeiss Conquest 3-9x40 for $350; Burris is offering a $50 rebate on their E1 series through the end of the month. Leupold's in this price range are always a favorite among hunters. And, there are a few other brands that regularly come up in these discussions. Good luck.