Update README to decrease unsuccessful drivebys (#4091)

README.md

@@ -58,6 +58,10 @@ docker run -it --pull=always \
 
 You'll find OpenHands running at [http://localhost:3000](http://localhost:3000)!
 
+You'll need a model provider and API key. One option that works well: [Claude 3.5 Sonnet](https://www.anthropic.com/api), but you have [many options](https://docs.all-hands.dev/modules/usage/llms).
+
+---
+
 You can also run OpenHands in a scriptable [headless mode](https://docs.all-hands.dev/modules/usage/how-to/headless-mode),
 or as an [interactive CLI](https://docs.all-hands.dev/modules/usage/how-to/cli-mode).