To set a shipping cost depending on an order total:
  1. In the administration panel, go to Administration > Shipping & Taxes > Shipping methods.
  2. Create the shipping method or choose the existing one.
  3. Click on the name of this shipping method. The Editing shipping method page will open.
  4. On that page open the Shipping charges tab.
  5. Select the desired location in the Show rates for location: box.
  6. In the Cost dependencies section in the first row enter 0 (for instance) into the More than input field and a shipping cost (e.g. 25) into the input field next to it.
  7. In the following row enter the total amount (e.g 50) after which you would like to change the shipping cost into the More than input field and different shipping cost (e.g. 20) into the input field next to it.
    NOTE: In this case if the order total is between $0 and $50, the shipping  cost will be $25, and if the order total exceeds $50, the shipping cost  will be $20.
  8. You are able to specify as many intervals as you like.
  9. Click the Create button.