Mail belongs to hunters and shamans (plus pre-40 warriors and paladins in the classic editions), making it one of the thinner armor markets.
Mail (Armor)
Auction-house prices and price history for Mail in MoP Classic.
1,706 items in Armor › Mail are currently auctionable in Mists of Pandaria Classic.
Prices refresh daily from TradeSkillMaster (TSM), so day-to-day gaps in lower-volume listings are expected rather than a collection problem.
Mail listings link to price-history pages with per-realm buyout, average, and median data for Mists of Pandaria Classic.