If you have any pawn shops around, take time to prowl them...Many take optics off of the rifles in the rack due to space and you can find some decent buys...Look for the Field of View specs...The wider the FoV, the more usable for predators...If you need to leave your drivers license with the shop owner, try to get the optic outside for viewing, rather than looking at it in the store lighting...
Like others, I question the BDC reticle need for the distance you state...Trigger time at the range will serve you better at various distances..I have a 2.8-10x (pawn shop purchase for $50) on my AR and seldom get it off of the lowest setting...Only if my target is either partially hidden or much farther away where I need the magnification for a clean shot do I crank it up....