As with everything, the main reason for a possible rip-off is ignorance. The less one knows about the process, the more easily one can be manipulated.
That being said, you don’t have to sign up for classes to get some idea of what it means to commission a website. Spend an hour on the web searching for hints; there are plenty of them nowadays.
You’ll probably find out that —
Pricing methods and website packages range from one hundred dollars to hundreds of thousands of dollars, depending on the size and complexity of the job.
Number of hours: the total number of hours is estimated and then multiplied by the hourly rate, which ranges from $50 to $150. Expect to pay more for original artwork, inclusion of database elements, or Flash content.
But then again, how can you know that the total number of hours presented to you is the real number, and not something that has been adjusted by addition or even multiplication?
Of course, you can’t.
But what you definitely can do, is write down each and every idea of yours about how your site should look, what message it should convey, what should be there and what should not — and then discuss all these points with the designer until he understands what you want, and you understand exactly what you are getting in the end.
Ask questions until you feel you understand.
Then bargain about the price.
Don’t assume that everybody will be trying to rip you off; there are many more honest folk in the designers’ community than not.
In the end, write everything down in as clear and detailed a way as you possibly can and make it your contract.