SQL Server Advice for an old hack
The easiest solution is actually free: Microsoft's Virtual Labs. You get access to SQL Servers in the cloud, plus step-by-step instructions on what to experiment with. (You aren't required to do their tutorials, either - you can use the VMs for anything you like.)

Keep in mind that there's a few restrictions: you can't surf the web from there, and you can't copy/paste things in. Because of that, it's a little limited - but you can't beat free.

If you're going to run your own SQL Server, I wouldn't recommend doing it in the cloud since you pay by the hour. You're better off using a free virtualization tool like Hyper-V, ESXi, or VirtualBox, and then installing the totally free SQL Server Developer Edition. Good luck on your learning journey!