Basic Commendation

Basic Commendations are an elder game commendation that can be earned by completing level 55 repeatable missions. They can be used to purchase specialty items from Basic commendation vendors. Basic Commendations have a max limit of 1000 and a weekly earning limit of 500.

Source
Basic Commendations are mission rewards that can be obtained from level 55 repeatable missions.
 * Mission reward