I would consider perhaps some movie tickets. He did, after all, use a the five dollars he won in the Beautiful Child contest in Meridian on going to the theatre quite often.
You might also consider using a picture or flyer for that same contest, because that is one of the first things he talked to Scout and Jem about.
Lastly, maybe something about Boo Radley? He was quite interested, as was Jem, in getting Boo Radley to come out. Be creative and think of something that might represent this poor, misunderstood man that ends up saving Scout and Jem in the end.