I have never really bothered about clothing but from what i have been told it can be very difficult for a new retailer to even get accounts with some clothing/footwear companies.
I know this as i only ever use 1 clothes shop ( yes because i get discount

) and the manager in there was explaining to me one day how the owner has most accounts himself but a lot of the other stock is bought from a buyer/wholesaler.It just so happened that the buyers premesis are above this particular clothes shop and the buyer himself was once the buyer for a large designer retailer in the area before setting up on his own.
As for quantities that the buyer can get i am not exactly sure but he does deal in most of the designer names.
Also the mark up for the reatil shop if they got direct was about 100% on clothes and 50% on footwear.If bought from the buyer then prob 5-10% less.
But the manager was explaining to me that to get direct accounts with some companies you have to have your retail outlet set to certain criteria ie floor tiles not carpeted etc.