Idle Off

I own a 2004 Toyota Corolla and the idle seems to be off. How can I fix that? And approximately how much would it cost me?

What do you mean by “the idle seems to be off”? Too high? Too low? Surging? If you have a tachometer, what is that reading? Also, we don’t do estimates. Parts cost and labor rates vary greatly throughout the country or even the world (some people on this forum live in places other than the U.S.). Describe the problem better and we can help you better.