Found that at Cabella's.com. No idea of the quality. I'm a bit of an optic snob and beleive there's a reason why quality optics can cost as much, and sometimes more, than the gun. IIRC my Aim Point, Mount, and BUIS on my AR cost over $600. Granted that's not as much as the gun in this case, but it is possible. And not one problem 2 years later. I'd personally rather go without and save up than buy something that is going to have to be replaced within a year.
My suggestion is get a good set of iron sights, fixed or flip up, (you'll need them if your red dot goes down) and then save up for an Aim Point, EO Tech, or ACOG.