MailChimp is a good example of aligning pricing with costs
I strongly disagree with that. You should align your pricing with the value the user receives. To do this optimally, you need to have a good grasp of who your user is, how much value he receives from the software and how the typical purchasing process looks like. For an early stage company, all these questions may not be answered yet, so it is best to wait and learn what the users do with the product before prematurely optimizing pricing at an early stage.
That said, if you have correctly priced your product, than the pricing should also align and scale with your costs, so you can use that as a quick short cut to evaluate a pricing model. When pricing doesn't scale with costs, it usually means your having properly valued your product.
I would argue that seems to be the case with the pricing for this Show HN