If you search for those items on eBay, check the worldwide option, and then the completed items option on the left side of the page. You'll be able to see if anything like that has been sold recently, and how much $ it fetched.
The used makeup has health implications. I toss eyeshadow that has only been used once by me after 3-4 months. It's against eBay rules to sell used cosmetic items but that doesn't mean it doesn't happen. Also, you may be able to swap some of it for something you or your mum wants on MakeupAlley.