Please find what you need, then, add to cart. After you add all you need into the cart, click the 'CHECKOUT'. Program will lead you to the checkout progress, it will tell you final costs. 

If you didn't find you need on the 'buy parts', you can also check the 'part's catalogues'. Check the pages, find what you need, should be a number of that page. Then, add to cart.

If you really can't find the product you want, you can contact our customer service. Their online hours are from 9 am to 9 pm, Beijing time.