[throwaway201103]

Oracle is very powerful. As a developer I found it easy to work with. But the cost to run in production is eye-watering. IDK how their licensing works today but in the past it was free to use for evaluation or for developing a prototype. Once you were "gaining business value" i.e. using it even if only internally to develop a real product, you were supposed to be paying for it.

[blendo]

Oracle XE is free for production use, but it only makes sense if

a) you are already familiar with Oracle, and

b) you have a very small data set:

“Oracle Database 18c XE supports up to:

3 Pluggable Databases

2 CPUs for foreground processes

2GB of RAM (SGA and PGA combined)

12GB of user data on disk (irrespective of compression factor)”