Gemini 2.5 Flash is Google's fast multimodal workhorse — a strong balance of speed, quality, and cost across text and images.
It's genuinely free via Google AI Studio: create an API key and you get a per-account daily quota (~250 requests/day at the time of writing), rate-limited, no credit card. Google sets the exact limits and they can change — check your AI Studio dashboard for live numbers. Google AI Pro subscribers also get $10/month in Cloud credits usable on the Gemini API.