Is Helm really free?
Helm is free as in freedom. This means you control this software, it doesn't control you.
In terms of money, Helm is pay what you want. So you are free to pay nothing.
Where does Helm store files?
Standalone - /usr/bin/helm
LV2 - /usr/lib/lv2/helm.lv2
VST - /usr/lib/lxvst/helm.so (if installed)
Local Presets - ~/.helm/patches
Factory Files - /usr/share/helm/
Config File - ~/.helm/Helm.config
Installation latest version into Linux Mint:
1. Download Deb package