Magento Tier Price feature can be used to give discounts on products on the basis of quantity.
Magento Tier Pricing is a default feature of Magento but it displays only label (table) on the product view page. We have developed this extension to display added quantity in dropdown and dynamically change the price on the product view page.
Magento Tier Price Extension is an enhanced feature of default tier price which will help your customers to select the quantity you want to sell. The customer can also have an idea of the unit price from the same page.