It isn't exploitive. Bowkers doesn't want to deal with selling ISBNs one at a time. They are a B2B company, not a retailer. They are use to dealing with companies that buy 10-1000 ISBNs at a time. They have been offering the single ISBN for years, but more as a "Good Gods! Fine! Here!" than an attempt to do business with individuals. You can buy 10 for $275 ($27.50 each). Frankly, if you only need one ISBN...you probably don't need an ISBN. ISBNs are really most needed for people who are going to make a concerted effort to push into brick and mortar stores and institutions like libraries with print offerings. Readers don't pay attention to the name on the ISBN.