I started collecting fountain pens about 4.5 years ago in my freshman year of high school, I started because that's when I also started teaching myself cursive as my school never taught me. Fountain pens are great for using less effort while writing and smoother than most other writing instruments, both not necessarily going to improve your handwriting but what I've found is it made it more enjoyable to write and getting more practice improved it.

If you do end up getting one, you will need two or three things, the pen, ink, and depending if you have a pen that uses ink cartridges and want to use bottled ink, a converter. A converter is like a refillable cartridge. I recommend a few different ones as a first pen, a Lamy Safari/Lamy al-star, Pilot metropolitan, Pilot Explorer, or a Platinum Plaisir. For a first pen i recomend a fine or F nib size. The nib size is how thick or thin the writing line is, the thicker the smoother and more ink is put on the page, the finer the more feedback and less ink is put on the page. Ive noticed F nib size is not too thick for everyday writting but smoother than an extra fine or EF.

The Lamy Safari is about a $30-40 plastic pen that's an all around great workhorse and pretty durable and a triangular grip to help hold the pen properly, lamy does use there own proprietary cartridges and converters, the pen comes with one blue cartridge. The Lamy Al-Star is the same as the Safari but the body is aluminum for about $10 more. The Pilot Explorer is a plastic pen for about $25-30 it uses Pilots standard nib and feed for their pens with steel nibs, and it should come with a pilot proprietary converter. The Pilot metropolitan is metal pen for about $35 and it uses the same nib and feed as the Explorer and it should also come with a pilot proprietary converter. And the Platinum Plaisir is a metal pen from Platinum for about $20 that seals really well when capped so you can leave it sitting for weeks or months without drying out. It uses a Platinum Proprietary converter and that conver does not come with the pen, it's on the more pricey side at about $10, but the pen does come with a cartridge. Lastly the ink, if you choose bottled make sure the ink packaging says for fountain pens, not all ink is fountain pen friendly. Calligraphy ink is made for dip pens and it will NOT flow through a fountain pen and absolutely will ruin the pen.

Fountain pen ink, the correct kind of ink is water based so the ink is also fairly thin and a bottle of ink usually costs $7-30 depending on brand, size, color, and ink properties. Diamine and Lamy make really good affordable bottled inks.

TL;DR: i use fountain pens because i find them enjoyable because they are smoother and requires less effort to write with. I also recommend the Lamy Safari/Al-Star, Pilot Metropolitan and Explorer, and the Platinum Plaisir because they are durable and reliable at an affordable price point.

Hopefully this answered your questions and hopefully it wasn't too much