Sponsorship vs. charging users, what would you do when your side project starts to grow?

A couple of months ago I launched lovableprompts.app, a tool that turns rough product ideas into optimized prompts for Lovable or others vibe coding platforms (Bolt, Cursor, Replit...)

It started as a fun side experiment. Now it’s used by 10k+ users, has generated thousands of products, and is slowly becoming a core part of many makers’ workflows.

But… costs are piling up (tokens, backend, hosting, etc.) and now I’m facing the classic dilemma: Should I look for a sponsor to keep it free for everyone, or start charging users?

Curious how others have handled this situation.

Any advice, experiences or even hard truths are very welcome 🙏