If he haven't got one already, buy him a cheap DMM (Digital Multimeter). It's the most useful single tool you could get him and it is actually indispensable when building robots as well as in general electronics (and for checking mains lamps and installations - but better not let him do that just yet).
I could be had for somewhere in the range of $4 to $10 in a hardware store or similar and its value to the kid will be a hundred times that
Paper on the other hand... Ever known a kid that would go *Yah* when getting paper?