I've come to rely on primer under foundation a lot more than I ever thought I would. It started with Benefit's Porefessional and since receiving this from the Leeds Blogger Meetup I have used it pretty much every time I have applied foundation. For those extra lazy days, that cross over with a good skin day, this is also good to just even out your skin tone and wear alone to make a your-face-but-better kind of transformation.
I use around half a pump for my whole face and apply with my fingers - if wearing alone then buffing it in with a flat top kabuki gives an even better finish. What initially struck me as quite a dark shade works fine as a base, but does require a bit of tan faking for a solo application.
This is the matte finish version of this cult label primer, and while wearing alone does achieve this, it isn't going to change the finish of your foundation. It does however, keep your make up fully intact for the day and works perfectly for that much needed extra layer for a night out.
It retails for a seemingly high £29, but with a little going a long way and 30ml of product compared to Benefit Porefessional 22ml - I think you might just be getting more for your money (any committed mathematicians feel free to disproof this).
What are your favourite primers?