Season 3 introduced the new personal rating system, which is a rating unique to each player in addition to their team rating. You must have a certain personal rating as well as team rating in order to purchase some of the Season 3 rewards. However, you do not have to maintain these ratings to continue use of the item.
Season 3 Weapons require a personal rating and team rating of 1,850 to purchase, while shoulder slot items require 2,000. The chest, legs, hands, and head slot items do not require a rating to purchase.
Season 2 items were made available at a 15% discount, while Season 1 items were made available for Honor Points and Battleground Tokens.