I think their are a number of scopes that would fit the bill, Bushnell, Nikon, Leupold, etc. The 3x9 is a solid choice and I prefer 50mm objectives. However I wouldn't suggest buying a lower model 50 mm, over a higher model(quality) 40 mm scope. A budget is a budget and if you don't or can't up it to match the scopes base quality than stick with a higher quality 40MM.

Everybody has their favorites and eyes are different, so really buy what you like and as much as you can afford in whatever brand, power and objective. I have had excellent results with bushnell elites -3200-4200, loopy vari x III and the Burris Sign. Series. So I wouldn't hesitate in pointing you to look at either one of those scopes. (However the last 2 would cost you more than 300.00) Other guys have mentioned the varix II or some say the VX II from Loopy, however I wasn't really blown away by either of these scopes and personally opted for the Bushnell Elite 4200 and payed much less. Just my opinion though!