I can answer this since I'm both.
A single family appraisal is $275-$300 right now. A 2-4 family is typically $400-$500. A relocation appraisal is typically $500.
And, I have to disagree with Elvis on this one. Appraisal is ALL about market value. You are far better off with an appraisal than a CMA. It is unbiased and objective. It is also far more in depth, and is a real value. Unfortunately most CMA's done by real estate agents have an agenda. To get the listing. There are some excellent agents who "tell it like it is", but with so many new and inexperienced agents in the workforce, the vast majority of "free CMA"s are worth what they cost. Let's face it, with many sellers, if you give them a true value, you can kiss the listing goodbye. So there is pressure on Realtors, especially new ones, or financially strapped ones, to come up with a "feel-good" value to get the listing.
I don't mean this as an insult to my fellow agents, I'm just being honest. And yes, there are experienced agents who know their areas like the back of their hand, who don't inflate to get the listing, and whose opinions are as good as that of a trained appraiser, maybe even better. But these are standout agents who have been in the business for a long time and have a lot of integrity. You have to remember, it only takes a few weeks to get a real estate license. There is no way an agent who has been in the business for 2 years or less is going to produce a CMA that I would have any faith in. Yet due to the extremely high turnover in our field, the typical agent is fairly new.
Finally, if your dealing with any important matter that could involve litigation, a CMA is utterly worthless. An appraisal by a licensed appraiser is mandatory in this arena.