I remember a great story from Sandra Kurtzig's book "CEO: Building a $400 Million Company from the Ground Up". She demoed her package to her first customer. He was wowed and asked , "How much?" She was worried about overpricing, but she said "$50,000" anyway. And when he didn't blink, she added, "per module." And when he still didn't object, "per year."

It really depends on who your customer is. Many managers have discretion up to $1000, so a few hundred dollars is not a hard sell. Above that gets into the corporate approval cycle. If you are selling enterprise software, you can get away with $2500 per seat, but then your selling cycle becomes months long.

If you are selling to consumers, maybe only a few dollars or a few $10's of dollars. Think TurboTax. Developers are the really cheap bastards, maybe $.05, But they can probably talk their managers into spending a couple of hundred dollars.