Sam's Club offers its members the Herman Miller Aeron Chair in Black, model no. AE113AWB, for $499 with free shipping. (Non-members pay an additional $49.90, so it's best to buy a 1-year membership for $45.) That's the lowest total price we could find by $105, although we saw it for $50 less last month. It features adjustable arms, lumbar support, 2.5" casters, and a graphite base.