Welcome to the community!
Yes!
Nope! Not anymore, unfortunately.
It’s unfortunately more confusing than necessary. Possibly due to legacy reasons.
You need to charge your account and preload some money (note that these credits may or may not expire within 1 year). Then you may or may not need to cycle your API keys before things start working.
the /5$ refers to your theoretical monthly(?) spending limit, it doesn’t actually reflect how much money you have in your account. Note that this has historically been unreliable.
I hope this helps you at least get started, let us know if you run into any more hitches!