He bought the Skittles and a can of Arizona Watermelon Iced Tea. Apparently one or both are used in combination with cough syrup to make a mixture to get high.
What struck me from the video, besides the obvious difference in sizes between the adult clerk and the “innocent little Trayvon” is that he looked stoned as he wandered in and around the store for 9 minutes.
And how long did it take him to go through his pockets to find the right amount of money to give to the clerk...