Thinking about trying out a fountain pen for the first time. What makes them so great???

I use the Journaling community on here quite a bit, and a lot of people on there talk about how switching to fountain pens has been a game changer for them. And I am thinking of giving them a try.

I typically gravitate towards Pilot G-2 pens (0.7 & 1.0) and Pentel Energels for my journaling.

As a beginner and based on my pen preferences, which fountain pen would be best to start with? I wish I could test one out before purchasing one. I mean, I guess I could maybe return it if I hate it.

Preferably a fountain pen that is not too expensive ($30 or less)

Thanks!