From In-Portal User Manual

Pricing

This tab allows you to set up the price brackets for the product. Each price bracket has a minimum quantity, a maximum quantity, a cost, and a price field, as well as a field for points (reserved for future use) and a ‘negotiated’ flag.
The minimum and maximum quantities define the bracket boundaries, and they are inclusive. All brackets must form a continuous range, meaning that the next bracket starts where the previous one ended. The administrator controls the beginning of the range and the ending – minimum and maximum quantities that are allowed for purchasing. There is a special character (infinity) to specify that the last bracket is open-ended (when there is no limit on how much can be purchased). To use this special character, click on the Infinity icon in the menu. In-commerce enforces the continuity of the range by allowing to enter only the maximum quantity for each bracket (with the exception of the first one), and that automatically becomes the minimum quantity of the next bracket.
The cost is an internal field, used for storing the information about the cost of the product when purchased from the manufacturer or distributor at that volume. It is not required, and currently only plays a role in the reports. The price field is not required, but extremely important – if left blank, the price is considered zero. If the negotiated field is checked, it means that the price is not determined at the time when the customer is placing an order, and it will be determined later outside of the system. This is useful for large orders, to give custom pricing to large volume buyers.
A few words on how to operate the brackets. To add new brackets, click on the More Brackets icon, and the system will add five more blank brackets at the bottom. Don’t worry about the unused brackets, they will be automatically cleaned up when you move to another tab or save the product. To insert a new bracket in-between existing ones, simply add it to the bottom, with the correct maximum quantity value. The system will arrange that as well. If you want to see how the arrangement looks, you can force it by clicking on the Arrange icon in the toolbar.
Let’s take a look at a specific case. For example, you want to have the following setup:

• Regular price - $10
• Required minimum purchase of 3
• If purchased more than 5 items, the price becomes $8 per item
• If purchasing more than 20 items, contact the store for special pricing

To achieve this in a new product, first click on More Brackets icon. This will get you 5 empty brackets. Enter ‘3’ in the minimum quantity of the first bracket, then 5 in the maximum, and price of $10. Moving on to the next bracket, enter 20 for the maximum quantity, and $8 for the price. Then place the cursor in the third bracket, click on the Infinity icon, leave the price blank and check the negotiated flag. Don’t be alarmed when the page refreshes after you click on Infinity – it’s just removing the extra unused brackets. Let’s say you forgot, that if your customers purchase 10 items or more, you want to give them another level of discounted price - $7 per item. No problem – there is no need to redo the brackets. Simply click on More Brackets again, and in the 4th bracket enter 10 for the maximum quantity. Then set the price to $8 (this will become your 5 – 10 item bracket), and change the price in your third bracket to $7. Now you can click on ‘Arrange’ to let the system sort everything out and to view the results. You are done!