I ran across this a few weeks ago and had to fiddle with it a bit before posting anything about it.
Fly.io will host a docker container 24×7 with FREE inbound data, 3GB of persistent storage, and 100GB of free outbound data (160GB in some regions) with a minimal charge for additional data (bandwidth or storage). What can you do with that? Bring up a Debian container for SSH; host your own VPN; host your own password management app; just fool around!
Before deploying your first app you’ll have to give them a funding source which CANNOT be a prepaid card (like one from Privacy.com) although you CAN buy credits (minimum $25) with a prepaid card. Be aware that they have systems in place to detect fraud and high resource utilization so once you’;ve signed up and given them a funding source, you still may not be able to fly launch because your account is marked as high risk, Just email firstname.lastname@example.org and they should be able to resolve it,