For my business, I rely highly on international reseller/retailers and many prefer to order online. Instead of doing a flat % off I give larger discounts for high quantities and depending on the item. Currently, I do this by either sending a PayPal invoice or adding products to a separate private page and adding special products there. Most resellers prefer using the website as to avoid wasted time for constant emails. The problem with what I do is there is no way to hide these products from regular users, making it possible for them to find them (using the search bar). Along with this, it is also much more time consuming to make new products for every product that is available to re-sellers.