What would be the best way to run a python script on the first of every month? 
My situation is I want some data sent to a HipChat room, using the python api, on the first of every month from AWS. The data I want sent is in a text file in a S3 bucket
Create a Lambda function and use cloudWatch ==> Events ==> Rules and configure it 
using:
1:AWS built in timers
2:Cron Expressions
In your case cron is better option
Best way to run scheduled code on AWS