Let's be clear from the start. If you consider power, speed, average and affordability, you can normally only have two or three in one player. For the sake of this article, and considering affordability a must in trade targets, most of these guys will not help your batting average.
That being said, these are trade targets who will boost your stolen bases without taking up a lineup space devoid of power. Unless your team is stocked with Adam Dunn-types and Dee Gordon-types, the 20/20 guys can make or break your team.
Keep in mind, my category-league teams rarely win the batting average category because I load up on 20/20 guys.