Question: I've tried searching for the answer but couldn't find it. Do the notes stored in Google Keep use space from the Google storage? Or is it free and unlimited like a Google doc in Google Drive?

EDIT: that's too good to believe they would give unlimited storage for pictures and audio recordings.

Any update?

Answer: 
As per the Google Product [forum answer](https://productforums.google.com/forum/#!topic/docs/_mgdBX6y53A;context-place=topicsearchin/docs/category$3Akeep$20storage$20space) no data attached to Google Drive account.
All the Google Keep data is stored in your android phone in main memory. The Default size appears to be 2 GB on my phone. When I used up the 2GB, it prompted me to give it more space, but by then the phone was almost full. I have not found the place where the settings are to change it yet. Seems Like a space hog. Wish I could just put it on the SD card.