...if after reading that you still have specific questions, ask.

You don't need a credit card, if you don't want to run it on Joyent's servers, you can run Triton for free on your own at home, at work, (or someone else's) infrastructure. All of that technology is freely available at Github at no cost other than reading a little bit of documentation and investing some time to set it up following the instructions.

Out of curiosity, do Digital Ocean, Hetzner, Azure or AWS not ask for a credit card?