The most cost effective logs archivial solution for Heroku.
Create S3 bucket and IAM user with programmatic write access to the bucket.
Sign up and setup LogBox.io application. Provide newly-created Amazon credentials and S3 bucket.
Tell Heroku to stream your logs to LogBox.io by adding generated drain URL. Service will automatically forward them to a configured S3 bucket.
heroku drains:add xxx:[email protected]
You pay for log volume per day.
Each 1GB costs $9.00/month.
There is no limit on the number of Heroku apps.
The first month is free. After the trial period is over, you will be able to select the appropriate plan based on the actual usage.