Your b2b trade program can leverage Tiers to provide different discounts & settings to different groups of customers. When a customer is assigned a tier, they automatically get the discount applied to items in their cart as they shop!
Currently tier default discount supports % and fixed discounts.
On the tier details page you can also modify Price Lists, which give you the ability to assign specific prices to products and quantity discounts. Simply run an export, and use the columns for price and quantity next to each product variant to assign prices.
Price Lists expect prices to be input in the default currency for the shop in whole units not cents. Should you need to input prices with fractional representation, you can do so still ie. 499.99
Please read & submit suggestions to the product roadmap - we're planning on implementing features for minimum + maximum orders, price sheets and product exclusions at the Tier level very soon!