if you're into pens, you'll end up at fountain pens in the long run, so might as well get started 😁 I like fountain pens cuz you keep using the body of the pen and don't have to throw out a whole pen every time the ink runs out. I try not to use too many disposable things if I can help it.

My favorites getting into it are Lamy Safari and TWSBI Go. I'd recommend the Safari to start out. A real workhorse.

As for ink, you can buy cartridges to make it easy to refill or you can go for a converter which is a reusable cartridge that you can fill up from an ink bottle.

For nib size, I prefer Fine or Extra Fine but it definitely comes down to personal preference.