I saw that, too. It's what eBay used to call a 'Dutch Auction'. The $75 you bid is on ONE box of film. When you place your bid, you can choose now many boxes you want to buy at that price, but it would be $75 for each box.
If you made a mistake thinking it was for all 2100 sheets, you can retract your bid and give the reason as 'entered wrong bid amount'. You can also e-mail the seller and ask him\her to cancel your bid because you didn't know it was a Dutch Auction - plead ignorance. Nothing bad will happen to you for retracting your bid - no matter what the dire warnings say.
I love deals like this - I know the film will be fine and I can shoot more shots with less thought of the economy of it - which is really a factor with 8x10 - my last box from B&H with shipping was about 150 - that is about $3 every time I go click - now I click twice as often and .... oh yea ..... each click is another separate 20 minitues in the dark room because I tray develope each one individueally. Well - I still bought 2 boxes - Thanks all for the heads up!
My photos are always without all that distracting color ...