Managed hosting is expensive to operate and self-managing kafka is a job in of itself. At my last employer they were spending six figures to run three low volume clusters before I did some work to get them off some enterprise features, which halved the cost, but it was still at least 5x the cost of running a mainstream queue. Don't use kafka if you just need queuing.
Cheapest MSK cluster is $100 a month and can easily run a dev/uat cluster with thousands of messages a second. They go up from there but we've made a lot of use of these and they are pretty useful
I've basically never had a problem with MSK brokers. The issue has usually been "why are we rebalancing?" and "why aren't we consuming?", i.e. client problems.
It's not the dev box with zero integrations/storage that's expensive. AWS was quoting us similar numbers for MSK. Part of the issue is that modern kafka has become synonymous with Confluent, and once you buy into those features, it is very difficult to go back. If you're already on AWS and just need queuing, start with SQS.
