One option is the Bushnell TRS-25 which can sometimes be found for $60 or less on sale.
Another might be this fiber optic sight called the See All Open Sight. People who've used on rifles say it's very fast for 2-eye acquisition of targets. It can be found here for $87 with shipping (also see the video) ...
http://www.slickguns.com/product/see-all-open-sigh-7499
There are a number of user reviews at Amazon. People suggest best use is on a rifle for outside (not indoor) shooting because the optic depends on external light.
http://www.amazon.com/Sight-Reticle-Rifles-Pistols-Batteries/dp/B009IDYBJ6
Here is the company website ...
https://seeallopensight.com/
Thanks. I think the Bushnell is what I'm looking for. I do indoor and outdoor shooting and the lower light might be an issue with the See All.