One of the hardest things to do as a jewelry artisan is to price and market your pieces. Personally, I think that if you use quality parts, work to make lasting/quality pieces, and back your work with good personal service, you can't fail. Prices need to be reasonable for the parts and the time/effort put into it. There really can't be a "formula" for that. I do start with what the parts cost me, but the pay per hour might be adjusted if the price comes out too high or too low for the piece. Yes, pricing is subjective. I'll say it. Isn't all art?
A great blog by Dr. David Weiman to help you with pricing and marketing if you're also a jewelry designer is: