UGH. The big Etsy Success article today (MIS)leads with a pricing formula. Pricing formulas need to have the Miss Cleo "For entertainment purposes only" disclaimer.
"Pricing" formulas give you a number based on what you spent to create an item. Use a formula to calculate your true cost. Know your true cost. If you can't sell what you're trying to sell for enough to cover your true cost and you're not doing it for fun/love/while you watch tv, reevaluate your business.
To PRICE an item, take the number of dollars a customer is willing to pay for that item in a reasonable amount of time. Multiply by 1. If you want to charge more than that number, spend more time on marketing and find customers who are willing to pay more.
Cost times 2? times 4? Well, it's possible. Miss Cleo gets it right, too.