So Sokka came to the races. He had certainly heard about the fact that Akito was in it. His sister practically wouldn't shut up about it really since apparently her and Akito were friends. So he had come primarily for him, not knowing that Zuko was actually in the line-up as well. So when Sokka sees Zuko's chariot actually rolling by at the end, Sokka just looks at Wan with a dumbfounded expression. "Zuko got into the Shagpar Race!? How on earth did he get the money!?"