Q: what is it, and what's it used for? how much does it normally cost?
A: It does just what it says...conceals. It's good for covering small problems like under eye circles, marks left from pimples etc. It is dabbed on the individual problem areas and then foundation (liquid, cream, or powder) is applied over it. If a person didn't use concealer, the darker marks would show from beneath the foundation and the skin wouldn't appear to be smooth and flawless when wearing the foundation. Depending on the brand, concealer can range from abou $5 or $6, up to about $20. Some of your higher brands are even more expensive than that. I use concealer by MAC and I highly recommend. It has a longer wear and the color choices are very close to true complexion.