Comment by PaulDavisThe1st

Reaper can be downloaded without paying anything for it. But in a wink-wink strategy, continued use of it after a certain period of time is supposed to be accompanied by paying for a license. This is not enforced. You can call this free if you wish, but it's all a bit wobbly.

Also, if you want to play with synthesis, then VCV Rack, which is truly free (but also comes in a for-cost version with a few more features) is likely the right place to start, or its even free-er cousin/fork Cardinal (which can even be run in your browser)

https://cardinal.kx.studio/ https://vcvrack.com/