Alert: some eBay vendors are advertising sub $100 reflex red dot sights as "holographic". I do not know whether the deception is deliberate or accidental or the result of simple ignorance.
I asked two vendors whether the sights were true holographic type, and one came clean, the other lied.
I believe that price can be an approximate guide: you get what you pay for. True holos cost several hundred $$.
So proceed with caution!