I think you have to buy or sell quite a few of their harps to become a dealer. And then you might get 10% off. Not that much. If you want a real discount, buy one second-hand.
Watch for a CPO (certified pre-owned) deal — sometimes they have really fantastic ‘discounts’. Also, the classifieds section of this website has some discounted harps as well.
Thank you for your advice, Saul and Katherine.