In order to find the prices for different quantities of a product, just follow these steps:
1. Go to the Product Catalogue, select the product category you are interested in (e.g. Posters) and then choose the specific product you want (e.g. Standard Uncoated Paper)
2. In the Product details page, scroll to the bottom and select "All prices and shipping"
3. In the next page, you will see all the prices for the different quantities allowed for that specific product.