I have 4 different red dots available. All in very good to excellent used condition.

Holosun 5507k micro red dot - $110
Holosun 510c reflex sight red reticle - $175
C More RTS2 red dot - same footprint as sig - $150
Sig Romeo 3 max red dot - $250

All listed for less than 1/2 of retail. Located in Richmond, but can ship on my dime for full asking price.