GOSH (By Superdrug) do a great eyebrow felt 'pen' in brown and black for a fiver. MAC and Stila do the same pens for about fifteen!
I was told by a makeup artist that it's worth spending money on tinted moisturiser (she recommended the Laura Mercier one because you only need a little as the pigment content is high) and foundation - also a good primer. Everything else you can go cheap on. And remember that often the expensive companies and cheaper ones are under the same umbrella so the Bourjois products are practically the same as Chanel.
I use almond oil/vitamin e oil and castor oil to clean my skin - it's never looked better. I realise this isn't to everyone's taste but it works for me.
Rimmel nail polishes - great selection of colours and cheap. Cien by Lidl - I use their body lotion and deodorant.
frizzbonce I used to only buy tinted moisturiser. Then I discovered that I couldn't tell whether I look better when I had Garnier BB or Bobbi Brown tinted moisturiser on. I think it will probably make a difference for foundation, as they go on quite quick and you need a good match. I only started looking cheap when I became a mum.
OneLittleToddle - if you can get a good match with a cheaper tinted moisturiser then go for it. I've got very pale skin with a yellow undertone - whooh very sexy - and the wrong colour makes me look like a dodgy tv presenter.
I bet you don't look cheap. It takes a while to come up for air and think about yourself again though.