Not cheap, but a great option for a night vision sight - Armasight AIM Advanced Integrated Mount - Night Vision to Rifle Scope Converter

This is a great option if you have a night vision monocular and want to turn it into a sight. It gives you the flexibility to use the QD mount so that you can still use your monocular by itself. If you plan on mounting it to an AR-15 it works, but I felt it was mounted a little low. I bought a .5 inch riser so it didn't feel as awkward to look through it. In addition, if you have back up iron sights (or any flip up sights) on your AR you will have to mount this sight well forward of the rear sight. Once again, a .5 inch riser allows this to clear the rear sight so you do not have to remove the sight, or mount the night vision sight too far forward. Overall this product works as advertised and I am happy with it.
Pros: cheap battery, well made, works
Cons: price, mounting issues

This review was written in the old system and had content requirements that are different than reviews written today.