Configure bulk discounts for each product in your store by creating a table of quantities and discount amounts. Choose from fixed price adjustments, percentage adjustments or set a fixed price for the product. Optionally choose roles the pricing rule should be applied for.
Choose how to tally the quantities used in the quantity pricing table. Choose to tally quantities based on the cart quantity of the product, each individual variation, each cart line item (useful when using Product Add-ons or Gravity Forms Add-ons), or based on categories in the cart.
Advanced product pricing is useful when you need to discount a product based on the quantity of something a shopper is purchasing. Optionally, advanced product pricing can be applied to existing customers who you have added to a role you configure, such as “Gold Members”.

Demo : https://woocommerce.com/products/dynamic-pricing/