Here's some great advice on how much to charge for your software, from Joel Splosky:
When you're setting a price, you're sending a signal. If your competitor's software ranges in price from about $100 to about $500, and you decide, heck, my product is about in the middle of the road, so I'll sell it for $300, well, what message do you think you're sending to your customers? You're telling them that you think your software is 'eh.' I have a better idea: charge $1350. Now your customers will think, 'oh, man, that stuff has to be the cat's whiskers since they're charging mad coin for it!'