In another post, someone points out that he is totally incapable of determining the price of something. I submit that he is correct. What most of us do not realize is that nobody is really capable of determining the price prior to the actual sale. Those folks on Antiques Roadshow are not giving a "true price". When someone gives you a "value", all they are really doing is that they are guessing based on their experience.
Back to the question of pricing our work: We do not know what someone will pay for what we develop until we actually ask for money. Likewise, we do not know what our company is worth until someone actually buys it.
How to put a price on something we develop? Ask someone what they would pay for it. When you have asked a number of people and have gotten a range of prices, put a price on it at about 30-50% more than the average price mentioned. You want a price high enough that people wince, but not so high that everyone walks away.