Aaron - I'm a firm believer in starting kids off with good solid equipment (even if it's second hand.) If you go with the single round or square Rome pie iron (cast iron) it'll only run $17.99 at Cabelas, and now and then they go on sale. If they're local, no shipping. Those aluminum ones are only $8 cheaper. $18 for Christmas fits my kid-gift rule - twice the child's age or $20, whichever is cheaper. Drops to $10 when the kid is over 15.
If your nephew is strong enough to manipulate the extra weight of the CI pie iron, I'd say go with that. Another option, if Cabela's has it, is the hamburger griller which is like the round pie iron, but slotted to grill burgers. No reason you couldn't also make sandwiches in it, too - so it would be a multi-tasker. I have one square and one double (rectangular) CI pie irons, and was thinking of adding the griller this year because I don't have a round CI pie iron.
You might also want to take a quick look at ebay - I picked up two vintage steel pie irons this summer which have much shorter handles, and look like they were designed to be used on a camp stove. They're about half the weight of the CI pie irons. I haven't perfected cooking time with them, and since they're lighter, things burn a bit faster. I was going to work on cook time over a diffuser on my indoor stove this winter...the handles are that short.
And if you get your nephew the CI pie iron, and he ends up not using it or losing interest, Uncle Aaron can always rehome it.
