When I worked in the clubhouse for the Syracuse Chiefs part of my job was distributing fan mail. Everyone would get a lot and the big prospects would get the most. Most guys signed almost everything that was sent to them. Far different than the big leagues and you will have much better luck going this route IMO. Now i've been out of the clubhouse for three years and the player atmosphere has changed a lot in that time. Players seem to be more guarded now w/ their signature as compared to the past. Just my 2 cents!
I like Lego's and Baseball Cards! The tough decision is which hobby gets to spend the extra money!