I got my Herman Miller Aeron for about a quarter of the retail price from the Design Within Reach (DWR) outlet in Brooklyn.

The outlet has a ton of many types of all the brand name chairs, but they are usually overstock or refurbished. They usually have 20-25% off sales pretty often (check their Instagram page for when they have sales), so that on-top of the discounted prices is what allows you to get the chairs for cheap (relative to the regular price).

The DWR location is a bit of a journey from Jersey City though, but they can ship (for a fee) if needed.