Benyamin, while being quite young at the time, is notably missing when Yosef is sold. Does he deserve a reward for not participating or was he simply not included and therefore is incidental in the story? The only way I can figure to determine the answer to this question is to determine if he in fact did receive a reward. Therefore...Did Benyamin receive a reward for not having participated sale of Yosef?
According the Chida, who says it in the name of the Rokeach (Brought in Vedibarta Bam):
So, while it wasn't a reward, Yosef gave only Binyamin 300 silver pieces, so that the other brothers, who did sell him, would lose out on 300 silver pieces. This would take place of the fine they halachically owed.
As @Alex pointed out in the comments, the Torah Sheleimah brings this idea down in the name of many Rishonim.