I cannot see ever putting out $20 or more for them because I buy pens all the time and they always seem to disappear. Some sort of pen thief gnome I guess.
My wife has a couple for doing caligraphy with but they sit in a drawer and are seldom used.
Wow.
I have not noticed a cartridge pen since ca 1970 - whenever the 19 cent Bic ballpoint showed up on campus.
I have a gold Cross for work, and the house has a couple of dozen Bics scattered about for occasional use.
I’ve tried some modern brands but always come back to my old Parker 51s and 21s. The 21, the less expensive model, is the most enjoyable pen I’ve ever used and I am probably in a minority that prefers the 21 over the 51. Plus, if one knows where to look…neglected antique shops, usually…vintage but perfectly good inks are widely available for cheap. I’ve acquired a healthy stock of old but good blacks, blues, greens and reds that will last me the rest o’ my days. I’m not a snob, though. Gel pens are okay but I admit that now my teeth grit whenever I have to use ballpoints.
People at work used to poke fun at my fp’s…poo-pooh’d them as a pretentious affectation…UNTIL they tried them. Now they see the charm and practicality (yes, they are practical if you know how to take care of them), and I’ve given away at least one to a happy recipient.
I have a Waterman fountain pen I got as a 21st present which I use for signing Really Important Stuff (letters, documents etc) but I learned long ago I just can’t have nice pens for “everyday” use as they invariably flee in abject terror when I’m not looking.
I’ve gone through two Space Pens and a Cross in the past year - they’ve just vanished off the face of the Earth so I can only assume they’re on the the Biro Planet enjoying the Biro equivalent of the good life*, since they’re sure as hell not on my desk at work or in my camera bag.
Ironically, my cheap quad-colour pen is never far away and the coffee mug of promotional/giveaway pens on my work desk seems to replenish itself when I’m not looking. In any case, I always make a point of always having two pens on me because there is nothing worse in my line of work than being caught without a pen when there’s news afoot. My fluctuating pen supply is at the point now that I stash pens all around the place so they’re handy when I need them in the same way Chow Yun-Fat characters stash handguns around teahouses in Hong Kong Action films so they never have to worry about being caught short when things get interesting.
I’ve heard the Lamy Safari fountain pens are quite good and designed for “everyday” use, though so I might look into one for second-tier stuff - transcribing interviews and making notes at the office, where I don’t have to worry about it escaping when I’m out in the field. 
*Douglas Adams was definitely onto something, since that’s the only logical explanation for the way pens keep vanishing.
I’m kind of undecided. On one hand, I like the feel of writing with a fountain pen, and very much like the way my handwriting looks when written with one. On the other hand, they’re a PITA to deal with for everyday writing because they leak, they dry out, they can’t fill out multi-part forms, and worst of all, you can’t generally hand them to someone else and expect that they’ll be able to use your fountain pen.
That said, I actually do own a couple cheap but decent pens- a Pelikan Pelikano and a Parker Vector, along with about 5 colors of ink by Noodler’s, Private Reserve and Parker.
They were great for notes in graduate school, but in the working world they weren’t nearly so handy, and they’ve ended up at the bottom of a box somewhere, in favor of the Uni-Ball Vision Elite pens in the blue-black (which happens to be almost the same as Noodler’s Legal Lapis)