It is the beginning of May 2018. My bill of about a dollar came in from AWS. It appears that I am paying $0.011 an hour for compute and a tiny amount for storage. I am using the Cloud9 development servers, the “free” level. So yes free is about a buck a month. I figure if I was more full-time on this project I would pay about $70 a month. I have the system shutdown after 30 mins of inactivity to keep the costs down. The is recommended by AWS.
Just some facts for anyone out there looking at Cloud9, nice and not that expensive but not free.