The cels are actually most likely from the AWS
500 and 1500 yen cel packs.  You usually get
between 5-10 cels in a pack.  the 1500yen packs
are the oversized cels and the 500yen cel packs
are the regular sized cels.  Now say on average
he got 7 cels per pack and 1/2 were the 1500yen 
packs and 1/2 were the 500 yen cel packs.  That
would mean that 315 cels would be approx 45 cel
packs.  So say 23 1500yen packs and 22 500yen 
packs, that would come to approx 45,500yen.  Which
is a lot less than the $900 he claims to have 
paid.