As for ballpoint pens, during stays in Japan I accumulated a small collection of multi-color ballpoint pens with extra thin tips, most of them from Mitsubishi. Small sketches and notes tend to look a bit tidier and the thin Japanese pens made for kanji writing are superior for this. Also changing colors is quite nice for note-taking.
See also Sailor and TWSBI for good everyday fountain pens.
Paper is a bigger issue with fountain pens. Avoid Moleskine, choose Rhodia.
If you travel, large increases in elevation will make the pen burp up some ink. So I always pack mine in a separate baggie wrapped in some tissue paper.
If you run out of ink, refilling it on the go is a royal pain in the ass. Once a fountain pen becomes your daily writer, you need to have a spare pen on hand. The Lamy has a convenient window to indicate the ink level, but it isn't 100% reliable. Personally I just use a nice gel pen that is wet enough for my taste as my backup.
Lamy cartridges are expensive. Expensive enough that I've switched my Lamy over to piston fill with a so-called "converter" to use a bottle of ink that should last years. OTOH, Pilot/Namiki cartridges are very inexpensive and I still use those in my Pilot Metro.
This story caused me to re-activate mine and a few other fountain pens I haven't used in a while.
[1] https://www.kaweco-pen.com/en/pens/fountain-pens/454/kaweco-...
But if you want something real cheap, I find that Platinum Preppy ($3) is also quite good.
Of course, the most I write by hand these days are notes or a shopping list, so no need for fountain pens for me.
If you are interested in an inexpensive practical fountain pen, you should look into the Lamy Safari. It is easy to maintain, writes smoothly, and feels good in the hand. It is my every day pen.
Quick drying "document" inks are also good for everyday use. They don't fade or smear.