I have another suggestion that falls in line with NoMercy's initial suggestion. I recently purchased Konus scope in 3-9X with a duplex reticle and a lighted center dot (option of switching between blue and red).
It has a 30 mm tube and I think its a 50 mm objective. It is well within your price range and the optics are plenty clear. The scope comes with a lifetime warranty (except electronics)

I use a Vortex Strikefire Red Dot sight it has zoom which is great for "ringing steel"

Thanks for all suggestions so far. I have been swapping out a couple scopes I already owned, and tried a couple others my son has mounted on his AR ... they all have some nice features, some better than others.

All your suggestions are valuable and are being considered, and thanks much for your input.