I agree about Tesco Make up - I use it a lot.
I would say invest in a good foundation, a good idea would be to go to Space NK if you have one near you, they are less pushy than House of Fraser type beauty counter assistants. They offer very good foundations such as Laura Mercier, Chantecaille and By Terry, all of which are good quality and coverage.
I like Bourjois and Urban Decay for eyeshadows, they are the best imo, a good range of colours and very good quality, they really stay on and have a good colour density. However, saying that, I got some free samples of Lancome eyeshadows last week (they have a really good offer on at the moment, have a look at House of Fraser), and the quality of Lancome eyeshadow is excellent.
Eyeliner - you don't need to spend a fortune on that, I use Collection 2000 liquid eyeliner for instance, which is the best I have ever tried.
Blusher - Tesco cream blush is very good, I use that a lot. Other than that Bourjois Cendre de Roses Bruin is the best bet (powder) blush.
I use cheap lipstick and lipgloss, I have never seen the need to spend money on that.
What I do swear by is eyeshadow colour - I would never use and eyebrow pencil because I would feel like something from the 60s, however I do buy a special eyeshadow powder. Emphasising your eyebrows really makes a difference to your face. I used to have a Bobbi Brown one but I lost it, I currently use a Loreal trio (2 neutral coloured eyeshadwos and one eyebrow colour, available in abour 4 different colourways) which is just as good.