Mention Gemini free tier

README.Rmd

@@ -58,7 +58,7 @@ If you're using ellmer inside your organisation, you'll be limited to what your
 
 - `chat_openai()` or `chat_claude()` are good places to start. `chat_openai()` defaults to **GPT-4o**, but you can use `model = "gpt-4o-mini"` for a cheaper, lower-quality model, or `model = "o1-mini"` for more complex reasoning. `chat_claude()` is also good; it defaults to **Claude 3.5 Sonnet**, which we have found to be particularly good at writing code.
 
-- `chat_gemini()` is great for large prompts because it has a much larger context window than other models. It allows up to 1 million tokens, compared to Claude 3.5 Sonnet's 200k and GPT-4o's 128k.
+- `chat_gemini()` is great for large prompts because it has a much larger context window than other models. It allows up to 1 million tokens, compared to Claude 3.5 Sonnet's 200k and GPT-4o's 128k. It also comes with a generous free tier (with the downside that [your data is used](https://ai.google.dev/gemini-api/terms#unpaid-services) to improve the model).
 
 - `chat_ollama()`, which uses [Ollama](https://ollama.com), allows you to run models on your own computer. While the biggest models you can run locally aren't as good as the state of the art hosted models, they don't share your data and are effectively free.
 

README.md

@@ -63,7 +63,10 @@ recommendations to help you get started:
 
 - `chat_gemini()` is great for large prompts because it has a much
   larger context window than other models. It allows up to 1 million
-  tokens, compared to Claude 3.5 Sonnet’s 200k and GPT-4o’s 128k.
+  tokens, compared to Claude 3.5 Sonnet’s 200k and GPT-4o’s 128k. It
+  also comes with a generous free tier (with the downside that [your
+  data is used](https://ai.google.dev/gemini-api/terms#unpaid-services)
+  to improve the model).
 
 - `chat_ollama()`, which uses [Ollama](https://ollama.com), allows you
   to run models on your own computer. While the biggest models you can