On google osuppliers only seem to be listed via e-bay. I cannot get to an actual osuppliers website or any other details of the business.
It has sold over 151,000 items on e-bay so is a big player but not all stuff is photographic and I don't recall seeing this name as a seller of paper in U.K. e-bay until very recently. I checked its film prices as well and they are equally outrageous.
In fact both paper and film prices are so outrageous that I cannot believe it can be offering either paper or film to N American e-bayers at anything like these prices.
It could simply be that they don't bother selling to the N American market and the paper selling to the U.K. is a speculative venture driven by what they see as a market in the U.K where we just accept high prices.
Anyway an item number is 230910602517 and this is MGIV VC Glossy 8x10 100 sheet box
Thanks for any help you can give to see if there is a N American price for such items