Thanks OP! Just placed my order and I'm selling my old GCN copy to a friend for 5 bucks, so this is only gonna be $15 for me.
I used GCO once in the past but it was a long time ago and they still took $10 off my order - I guess I used a different card or they didn't keep track of the accounts...
Doesn't sound like it's an issue anymore, but I was gonna confirm that Amazon will use a box. I ordered Tales of Phantasia for GBA, single item, and the thing came in a box the size of a console with tons of bubble wrap all over.