Oh, yikes. I was interested in following up reading about kdb and now I am not.

cost is for commercial license only

free for personal use for 12 months, then you click some buttons to renew another 12 months, etc https://kx.com/kdb-personal-edition-download/

Per core

Azure has prices that vary:

https://azuremarketplace.microsoft.com/en-us/marketplace/app...

That's for commercial though.

One can get a personal use license for hobbies as other commenters have pointed out.

People paying $MM/year for SaaS that does less, but have prettier websites

No doubt, kdb/q is offers a of bang for buck in a commercial scenario. We use it and for some stuff it's good value, aside from staffing costs.