I was approached by people that want a developer with a certain expertise, but I'm not an expert in the matter. Should I adjust my rates, take the time to learn the technology and not charge for it or just charge regular rates and make sure they understand that I'm not an expert?
Yours is a common question! There are a great many factors you must consider when setting your price/rates. People tend to penalize themselves both when they are experts and when they are not.
SMARTSTART has published a guide specifically about Pricing that teaches people how to put the right price on anything you sell. You can get a free copy at http://smartstartcoach.com/smartstart-pricing/
It has helped a great many business owners. I encourage you to download it, read the whole thing (it's under 100 pages) and do the pricing assessments included in it before setting your rates.
As you'll see within it, "level of expertise" is not the most critical factor in pricing and your price is an important form of communication to your client. Hope the eBook helps you with this. -- Linda