So, my last trip to Cardiff had me doing the same thing but in MAC with their Back-2-MAC scheme. If you take back 6 packages, you get a free lipstick, lipgloss or shadow. However this only works in the stand alone shops, in the stands in places like Debenhams they're narrowed down to lipstick or lipglass - I think. Best thing is the packaging doesn't have to be empty. So if you don't like a product, don't throw it out!!!!
I got the lipstick in the shade Snob it's this really nice pale pink. It sort of has shades of lilac in it too and although that can make it hard to wear on some skin tones it's still a really gorgeous colour and if it suits you, go for it! I love it as a sort of splash of colour with a really neutral face.
It's a really nice soft lipstick and isn't drying in the slightest. Although most of the MAC lipstick aren't, some, including Russian Red can flake your lips and make you feel like you need some gloss! Fully pigmented and opaque in one or two slides across your lips. Absolutely great colour!