Definately more than $1. Even a polarbear in a snowstorm (no ink) costs
more because the paper, assuming it is anything decent, costs more,
unless perhaps if it is roll paper and he gets a very good price on it.
In general, on a quality paper, consider $.75-$1 per Square foot and ink
$1.50-$2 per square foot, if he is using Epson OEM cartridges or better.
Of course, it depends upon how much ink coverage the image demands,
but I would say $3-5 per print would be a reasonable cost on a 12" x 16"
print (and that assumes he gets a good one first time).
Art