Buy a car and there's a good chance you'll get hit with what's called a "documentation fee." This is an extra charge, often hundreds of dollars in some states, that supposedly covers the dealership's cost to handle the paperwork for that purchase. (The documentation fee is capped at $150 here in Washington.)

The problem is this fee catches a lot of people by surprise.

"The documentation fee is not listed on the sticker, you don't find out about it until you actually see the contract for the car," said Philip Reed, senior consumer advice editor at Edmunds.com.

Reed told me car buyers should consider the doc fee negotiable.

"A lot of people find it easier to negotiate a better price on the car than to try to negotiate the doc fee, but it is possible to tell the dealer take it or leave it, I'm not paying the doc fee," Reed said me.

The danger there, Reed pointed out, is that the dealership will look for other ways to recoup that profit.

"So the earlier you know about this, the better and less stressful it is for you to deal with it," he said.

According to Edmunds.com, the average documentation fee here in Washington is about $150.

More Info: What Are Car Dealership Documentation Fees?