Do not ask people who do not pay money for software how much money to charge for software.
If they're trying to undercut their competitors, I think it may be an error.. Charging $20, rather than $400 will make people think it's cut-rate, and not up to the challenge. No one who's making a professional/moneymaking website will be stopped by a $400 charge.
This makes me suspect that perhaps they're after the Wix/weebly market. Drag and Drop a website, rather than a professional-level tool. These tools are consumer facing, and don't generally resemble the Atlas versions I've seen much.
Don't get me wrong, I'm excited about Atlas, and look forward to buying a copy, but I'd rather do so knowing that that company is making enough to hire competetant engineers to keep expanding it! ;)
Also, I see from the comments on carsonified that they're going to charge $20 for the IDE. If anyone watches the video, I'd be interested to have that verified.