chore: expand on pricing

Author: lukeify

Fly.io.md

@@ -1,7 +1,20 @@
 # Fly.io
 
-## Pricing
+No IaC story at the moment. Had a previous terraform provider but was discontinued. Manage infrastructure through the web GUI or `flyctl` CLI.
 
-* "RootFS" $0.15/GB/month
-* Shared 1x CPU machines
-* $5 free allowance/month
+## [Pricing][1]
+
+There is no "free allowance" on new fly.io plans (referred to as "Pay As You Go"), instead, you pay for compute resources as you use them.
+
+For the majority of apps, fly machines in the `shared-cpu-1x` category will be sufficient.
+As an example, for a near-stock Rails app that was deployed to the Sydney region, the resources created were:
+
+* A `shared-cpu-1x-1024` maachine to host the Rails app proper (incurring a US$7.23/mo bill).
+* An additional `shared-cpu-1x-256` to support the corresponding database (US$2.47/mo).
+* A volume to back the data stored in this database (initially a 1GB volume, billed at US$0.15/GB/mo).
+
+Apps that are shutdown but persist on Fly.io accumulate a RootFS storage fee of $0.15/GB/month—this covers the cost of the file system, and is based on your OCI image generated from your app.
+[This change took effect from April 2024][2].
+
+[1]: https://fly.io/docs/about/pricing/
+[2]: https://community.fly.io/t/we-are-going-to-start-collecting-charges-for-stopped-machines-rootfs-starting-april-25th/17825