basically what it says in the top

Well some foundation's have recommendations, like for oily or dry skin or combitnation. Although most don't, I think.

I used to have really bad skin and I couldn't find a suitable foundation, so I just used a tinted moisturiser
Also my skin can get oily at times, so I use a powdered mineral foundation.. it helps, absorbs shine. Somehow..

I personally use Cover Girl Clean Makeup.

I think it works pretty well...

if you have oily skin you might want to focus on facial cleansers and lotions,,,

I think Clean&Clean works WONDERS and the lotion that is oil-free hydrates the skin very well.

As for dry skin,, I suggest using a facial lotion before you apply any makeup. I again use oil-free lotion because though my face is dry, I don't want it to go back to being super oily.

You can buy a right foundation if you reduce the oiliness of the skin. this will make your skin to normal/dry. You go find one that goes for normal skin.

you can apply moisturizer on dry skin to get oily-looking skin, and find one that is for oily skin.

"oil free"

I'd say you stay away from the oily ones and go to the oil-free as the member above me said. I know there's something from clean and clear that adds moisture before applying the foundation.

Oily - When using liquid foundations, look for oil-free kinds. Although, powder foundation is suitable for oily skin. If shininess is a real problem, try using a matte-ifying lotion (MAC has a good one here), and always, ALWAYS follow up with a sheer loose or pressed powder to set your foundation. Carry around oil-blotting sheets.

Dry - Don't even think about putting on foundation without using a makeup primer, or a heavy-duty moisturizer with SPF. You'll know if you need this if your foundation often comes off in flakes from your skin. I'd say to use a liquid foundation, although if your skin is extremely dry, you can try dabbing a foundation brush in moisturizer, then dipping it in your liquid foundation and applying it to your face in downward strokes.

my skin is dry yet oily at the same time so im screwed. i have bought bare minerals but it makes my skin orange