Just got a price list for Windows Vista and 2007 Office System from a reseller, and the accuracy is absolutely correct. It's enough for everyone to have a general idea.
Microsoft License Price Levels: 1. OLP NL: A minimum purchase of 5 licenses is required, and the purchased licenses can be any combination of products and product types; 2. OLP C: The price level is determined by the total point value of the licenses in the same product pool based on the initial order, reaching 500 points qualifies as level C. Renewal within two years can enjoy the same price level, and there is no restriction on the quantity purchased during renewal.
Please note: The above prices are the purchasing prices for resellers, not the retail prices for consumers. In other words, the retail price will only be higher, not lower.