- Patreon if what you're doing lends itself to regular updates
- PayPal or other payment processor if your project could use donations
- Subscription based Server As A Service for things that need data syncing between multiple platforms (eg: the public/client parts can be Free Software, the server part just exposes an API, and you make it clear what data is transmitted to the server remaining solely on the user's device)
- Consultancy to assist with installation/training if your product is complex
sevagh|1 year ago