Use as little of it as possible.
While you may be tempted to cover up every blemish now, I assure you, you will make it worse for doing so and no one sees the flaws in your skin to the extent you do. And while you might think slapping tons of make up on makes you look more mature, it really has the opposite effect.
I refused to use foundations and cover ups in high school and at the time many of my girlfriends thought it was odd. Now, 15 years later they all look about 15 years older than I do, from having that crap suck the moisture out of their faces for the last 2 decades.
Miss Crayon has some good advice, I would add to what she said - don't scrimp and buy cheap stuff. It's better to have less product and have them all be higher quality and less damaging to your skin than to buy a shit load of cheap product that will block your pores, make you break out and blemish more.
Also, as soon as you're home for the evening, scrub that stuff off your face to keep your pores clear and clean, and let your skin breath. I've always found make up wipes, while expensive make this easier. Cover girl's got a nice eye and lip make up remover that's easy to use too. Besides that the only things I've ever used on my face are baby soap and aloe vera moisturizer.
Lastly, to save money while buying the good stuff - get a Shopper's Optimum points card and keep an eye on their web site (or get on their email list). Keep an eye out for when they have their 20x points on make up events (sometimes it's even 50x points on specific brands) and buy the bulk of your product then. Later you can cash in the points you gain to buy more product later. Keep an eye out for sales and deals on your favorites and stock up when they go on sale.
Good luck!