A company I worked for paid £20k for a series of brand logo's. As this was a worldwide brand all manner of discussions took place on the merits of a design including the psychology behind it, the message it gave, the recognition it would develop etc.
I still think they overpaid, but the process did take months of meetings, examples were adapted or dismissed and so on. In the end, the company had 30 prime examples, all with subtle variances, and they chose the one they liked. The logo had no monetary value in reality, but the process of choosing it, and understanding the reasons behind the choice took all the time and money.
As others have said, a logo's price is based on the need for it and its use. If you want an image at the top of a page, a designer can deliver one out in an hour and charge you £30. If you want a brand design, that will be seen on every single bit of stock, contact info or promotion you deliver, you will pay a LOT more.
Also it depends if you want an image designed, or ar happy with a text design. I can do text designs like most other people, but if you want something illustrated, you need a suitably qualified graphic designer who has knowledge of various software including Photoshop, Illustrator, Fireworks, Coreldraw and can also draw freehand and build a design concept up from scratch, and that I'm afraid takes money and time.
I read an article once that stated the most vauable part of Nike's business was it's logo, it was known worldwide and transended languages. Apparently at one stage the brand logo, was worth more than the company itself, or something like that.
So your logo's price is based purely on the value you place on its need and use.