Now im not promiting something that I made, I just came across it on the net. It is an extension for Google chrome only
I'm sure that you will figure out how to use it.
https://chrome.google.com/webstore/detail/lcdkndlfcidmfboginpipenajinljndp
---- What does it do?----
When you are on HK and you are looking at an item it checks its database for buddy codes on that item and will show you in a box in the top right of the page of the discount. and if you buy an item without using a buddy code (or it didn't have one in their database) it will check after you buy the item if there is a code for it and then add it to its database.
So the more people that use this the more everyone will get things cheaper!
I hope this makes scene helps.