No model is free, I have to pay tokens for each translation, you can check the gemini api for pricing, and with 5 credits, you can translate 30 images with gemini-flash, is that not enough for you to test things out? you can even login to have 5 more credits, so it can be 60, 90, ... translations if you have multiple accounts to test. Nothing is free, especially with the heavy computing like this service, so I hope you can understand