You seem to be under the illusion that pricing has a direct relationship to cost. That's backwards. Pricing is based on the perceived value to the customer, n

You seem to be under the illusion that pricing has a direct relationship to cost. That's backwards. Pricing is based on the perceived value to the customer, not the cost to the producer. Dropbox and GitHub are offering very different services, and are therefore pricing their services differently, based on what they believe the market will bear. If you're trying to price a new service, I recommend you think about the value you are offering your customers, and how they perceive it. That will tell you what you are able to charge.