Instructions:Buycosmetics have recently update and improved their website, and they are offering 10% off everything to celebrate. Follow the link, and all discounts should be activated. There does not appear to be a minimum spend for this offer. If the direct link does not automatically activate the promo (you'd see a popup in the middle of the screen) - then use the voucher code above.
Worth checking out is their clearance section at the top right of the page - there are always a few bargains in there.