Club Membership

Can you offer your customers some kind of club membership that ties them in, or gives them a reason to buy more from you?  For example, could you introduce Gold, Silver and Bronze awards, based on volume of sales?  Customers awarded ‘Gold Membership’ may get preferential payment terms, sales discounts, a dedicated account manager etc…  Membership offers an opportunity to achieve buy-in by creating a marketable ‘package’ from incentives that you may already offer in an informal way (that your customers don’t necessarily appreciate they are getting).