So, for example, you can buy one copy of Richardson's Learning and Using the International Language, one copy of Step by Step, and one copy of Benson's Comprehensive English-Esperanto Dictionary - you will receive a 33% discount on all three. If you add another book in this category, you will receive a 33% discount on that book also.
If you buy two or more copies of any book, each copy counts against the minimum of three. So you can buy two copies of Richardson and one of Step by Step and get the discount on all three.
Quantity Discount Restrictions: All books must be purchased in one order and sent to only one address