Shopify's own Stocky app does that https://apps.shopify.com/stocky It's free on all plans except basic (or it used to be, notice they've changed it to say free with POS Pro, so might be worth checking on that).
Hi, my app Simple Purchase Orders https://apps.shopify.com/simple-po can definitely help you out. It allows you to set up suppliers and import products and their cost prices. You can then automatically generate purchase orders to reorder stock and transfer it into your Shopify inventory when it arrives.
Please check it out and let me know if you have any questions