What should I get from duty free?

[LowLevelWhinging]

I love airport shopping but always feel a bit overwhelmed at the choice in the beauty section.

Any tips for what to get?

Er... What do you need?

ha!

I don't need anything!

But, ok, I'd like a better foundation. Laura Mercier tinted moisturiser isn't doing me so many favours these days and disappears by lunchtime.