Reticle Sights

I did a search and did not find what I was looking for so if this is a repeat thread I apologize.

I am a new to the AR 15 world. If somebody could give me some basics on red/green dot reticle sights that would be appreciated. I THINK this is something I would like and benefit from but know absolutely nothing about them. I see the price range is from below $50 to $500 plus. It would be nice to try something on the low end $ just to see if it works for me like I think it will.
Any advice, information or suggestions is welcome.
Thank you!

There is a wealth of information here regarding these sighting systems.

The best known and most widely used sights of this type are Aimpoint and EOTech. Each differs slightly in how it “draws” the reticle. The Aimpoint is referred to as a red dot sight and the EOTech is a reflex sight.

Do a quick search again with some of these terms and you’re sure to uncover plenty of reading material to help guide you in your search.