CodeSkulptor is a freely available tool for running Python code in your browser. No installation is needed, and you can save and share your code as url links. It does not have the full spectrum of Python functionality and you cannot do anything too computationally time-consuming, but it still has quite a bit of standard functionality and it's very easy for beginners to use.
It always pre-loads with sample code. Delete it and write your own code.
You can even download or save code snippets as urls and share them.
Example: