Best bang for the buck - Trijicon AccuPower RS-20 3-9x40mm Rifle Scope, 1" Tube, Second Focal Plane (SFP)

Just buy one you won't regret it. I've had nightforce and uso scopes before and I will tell you the quality that trijicon is putting out will not leave you disappointed even when compared to very high end stuff. I have several accupower scopes and they all work well and maintain zero no matter how hard I beat on them