I recently acquired a mossberg slug gun and I am looking for and inexpensive scope that can reach out to about 200yards and can take the abuse of 12ga. I would like to see what you guys recommend and are using on your boomsticks
There's nothing remarkable about 12 gauge recoil that any standard scope can't handle, even with 3" slugs.
The term "affordable" is pretty nebulous, but there's no reason that an ordinary Bushnell 3-9x40mm or other comparable scope in the $100-$200 range wouldn't get the job done out to 200 yards, assuming (of course) that your unaided vision or corrected vision is at least 20/20.
Paying 3 times as much will either pay for a big name (Nikon, etc.) with some features that may or not be necessary and more QC, or one of the rare American makes of scope (Leupold/Redfield, U.S. Optics, some Nightforce).
I wouldn't pay any less than 100 bills for one to ensure decent quality.
Definitely pay special attention to eye relief and accept no scope with less than 4" of eye relief, especially if you intend to shoot 3" or 2-3/4" magnum loads.
Edit: Four brands of scope to actively avoid are BSA, Tasco, NCStar, and especially Barska.
My .30-06 has a Leupold VariX-III (1989 vintage) 2.5-8x36mm, and it's every bit as good as a Leupold should be.
Leupold still makes basically the same scope, slightly relabeled as the VX-III in the exact same power range and lens dimensions. http://www.opticsplanet.com/leupold-vx3-25-8x36mm-rifle-scope.html
On the midrange of the scale, my Marlin 1894 has a scope that is really surprisingly high quality, especially for the ~$150 I paid for it, the Hawk Varmint Special 2.5-10x44mm.
I especially like being able to get a really nice half mil-dot reticle and side focus to allow easy parallax adjustment.
I wrote a fairly detailed review of this scope on Amazon here - http://www.amazon.com/review/R1VLZ7...D=3375251&store=sporting-goods#wasThisHelpful