possibly, Eddie - I sell a lot on eBay and rarely have enough stout boxes to pack stuff in, so to OH's despair I collect any I see. However - not £15 for one box, no, £15 for a big pile of boxes is a possibility!
Added value for 'boxed'. Didn't know that happened with photographic, but it certainly does with toys and the principle is the same. Collectors may pay hundreds for an original box in mint condition for a toy, such as a rare Dinky, because a toy which is mint but without the box is worth so much less; the toy is then "mint and boxed". There's even a business in making replica, fake, boxes.
Fred I agree with toys but i sell photographic items all the time and the box mkes little diffrence. A toy is displayed in the box but a camera lens has to work , it's the condition that counts box or not.