In order to have your WooCommerce shopping cart display affiliate links, you will have to change the product type to ‘External/Affiliate product’.

Select External/Affiliate
After you change the product type just enter in the link to the external site (in this case) or the affiliate link (be sure to include the data after the question mark in the URL so that you get credit for the affiliate link).
An example of an affiliate link is https://rover.ebay.com/rover/1/711-53200-19255-0/1?mpre=https%3A%2F%2Fwww.ebay.com%2Fitm%2F2005-Ford-Mustang-GT%2F303158466387%3Fhash%3Ditem4695a71753%3Ag%3AFvcAAOSwV9RcpqMC&campid=5338534859&toolid=20008

Enter in affiliate link here
Some of you may have noticed a problem. Even though the ‘Buy Product’ is listed there, a couple of PayPal buttons may also be there which can screw up people trying to purchase this product.

Disable PayPal Checkout
As of May 21st, 2019 WooCommerce has not rectified this so if you have any products that are external/affiliate you will have to go to WooCommerce > Settings > Payment Methods and disable ‘PayPal Checkout’ then click ‘Save Changes’ to fix this. This will get rid of the PayPal buttons but don’t worry you can still have people purchase your products using PayPal.