Usually anyone using the FILLZ program is dealing with a large inventory, I mostly see it on Ebay with large book retailers. It basically is a subscription program that let's you list large inventory quantities along the different sites without having to list seperately on each. Ebay / Amazon / Alibres / Abesbooks, as long as it has an ISBN.

Hmm... I bought one earlier this year from someone very, very far from Nevada, and when he learned I was a fellow Canuck, offered to ship me a nicer one than was auctioned...

which was really great, though maybe also suggestive that there are more sw H1s out there...