How do companies that earn from production determine their prices?

Basically… what i would like to know is, if i have developed a product that i feel is good enough to sell. what would be the best way of determining how much to charge for the product?

So far, anything i have ever made and sold has had its price calculated on just two variables. the time spent developing it, and what the competitiors are asking.

is there any kind of high flying businessman formula for determining this kind of thing?

ps. i have no expenses to take in to consideration.