If you’d like to experiment with no commitment, look for a Pilot Varsity or Pilot V Pen. They are sealed disposable fountain pens.

There is some minimal upkeep. It depends strongly on what types of ink you use. If you use a very dependable brand like Parker/Lamy/Pilot, and only use that brand of ink, then the most you need to do is flush out old ink with water sometimes. This is not always required, but can avoid an odd stage where you’ve just switched to a new color of ink, and your handwriting slowly fades from the old color to the new color (some of us enjoy this, and some do not). The other time you might need to rinse is if you don’t use the pen for a long time, and the old ink dries out in the pen. The crusty dry old ink can clog your pen.

You should rinse out a brand new pen before first use, to avoid any traces of oils from manufacture messing with your ink as well.

However, a lot of the fun is the vast array of colors in the ink spectrum. If you are filling a pen from bottles of ink, always read reviews of that brand and specific ink color. You can usually find out if an ink is prone to issues or best in a certain type of pen or nib before you buy.