cost for both DynamoDB and Amazon Redshift can both get out of hands real quickly. I've seen it first hand. With Redshift, the problem is that data teams do not adjust the default configuration of 5 query slots. So when things slow down, instead of increasing concurrency for a given node, they add more nodes. I've seen monthly invoices of $100K+ for a workload that could have been done with less than a $2,000 / month.