We will be announcing very clear pricing when it goes into GA. Needless to say, serverless makes for a much much cheaper (and robust) operation than VPS and traditional clusters.

If you pull an application apart and squeeze it into managed services, your costs can drop by an order of magnitude depending on your availability requirements, engineering related costs, etc. A good article written by Spotinst's CEO [1]

Not trying to shill, not everything should be serverless, and I should work to be more platform agnostic, but AWS has been great to and for me, AWS marketing material [2]

[1] https://medium.com/@amiram_26122/the-hidden-costs-of-serverl...

[2] https://aws.amazon.com/serverless/

If you can leverage caching solutions (client, CDN, etc.) it could be a good chunk cheaper.

Maybe it simply leads to smaller teams and you save in employee costs.