How do Interior Designers price their services?

Just writing this question makes my head want to explode.  This is a daunting question.  Since there is no regulating body, there are about as many different pricing structures as there are interior designers.  There is not a one size fits all for designers or clients, the bottom line is: as the client do you feel comfortable and do you understand how you’ll be charged.   Do not be afraid to ask the designer to explain further before you sign the contract.   Alright, let's get into pricing.