I'm running on Google Cloud. I was looking at the costs and I noticed something weird - every week the daily cost of running machines is going down, and then on the 1st day of the month, it goes back up.
It's "jumping" between $1/day up to $2.5/day, so it's very significant.
This is a screenshot of the cost breakdown of running one machine with 2 vCPUs, 7.5 GB RAM in europe-west.
Why is it going up and down? Is there any way to keep it at $1/day?
The prices don't change, but an increasing discount is applied when your instances run longer.
Google Compute offers a sustained use discount for running specific Compute Engine resources a significant portion of the billing month. The discounts come in a couple of tiers and start to apply after running first 25% of a month, then increase after running 50% and 75% of the month. See https://cloud.google.com/compute/docs/sustained-use-discounts
An alternative to the automatically applied sustained use discount is the committed use discount, where signing up for one or three years is awarded with a discount: https://cloud.google.com/compute/docs/instances/signing-up-committed-use-discounts
