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.
I can't believe that Lamy Safari is still on market. I used mine up to Abitur (German A-levels) and must have bought it almost 20 years ago. By the end of grammar school I found Online Rollerball, which is a ballpoint pen with standard ink and ink cartridges. I still buy the latter from time to time.
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.
+1 for the Lamy Safari. It's an excellent writer, and if you lose one (an everyday hazard with an everyday pen), it's going to have cost you about 20 USD.
See also Sailor and TWSBI for good everyday fountain pens.
Question for the Lamy and TWSBI users: Does it work as an "in-your-pocket" pen? In other words, can I use it on the go, or is it meant to be kept at a desk?
In short, yes. Both are very dry with extra fine nib i.e. less ink on paper and dry very fast, both are affordable and you won't mind having on scratch on.
I might want to consider Pilot metropolitan too.
The importance of paper quality depends on which ink you're using. I like Noodler's Black, because it writes well even on cheap paper. It starts reliably and it doesn't feather (spread horizontally) or bleed through the paper easily. I've tried many other inks, trading samples with other fountain pen users, and I never found anything else so trouble-free.
Ink spread and feathering on cheap paper is unfortunate and frustrating. I would also add pretty much any pigment or iron gall-based ink to your suggestion. Unlike dye-based inks, i.e. the vast majority of your vibrant colors on the market, these contain tiny particles that are (with a little bit of oversimplification) permanently trapped in the cellulose fibers of paper as you write. The end results is that these inks are waterproof and don't show the dreaded feathering/bleeding on cheaper paper. I recommend the Rohrer and Klingner Salix and Scabiosa, two inexpensive iron gall inks (blue-black and purple-gray), Sailor Kiwa Guro and Sei Boku (pigmented black and blue) and the Platinum pigmented inks (available in blue, red and black IIRC). The Salix and Sei Boku have worked wonderfully for me on copier paper with no clogging/cleaning issues so far.
I have a Mont Blanc fountain pen, which I want to use as my main pen but cannot due to the ink spreading and bleeding through cheap notebook paper. Thank you for the ink suggestion.
I should point out that I use a Lamy Safari, which has moderate ink flow. If your Mont Blanc is an exceptionally wet writer, and you don't want to get the nib adjusted, you might want to try Noodler's X Feather, which is a version of Noodler's Black with even lower feathering (at the cost of longer drying time). But I suspect the drying time could be annoying, because Noodler's Black is already somewhat slow drying.
I enjoy writing with my fountain pens (I own a Lamy Safari and a Pilot Metro). But, there are some real-word gotchas:
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.
As an in-your-pocket pen I'd recommend a Kaweco Sport pen [1]. They are smaller than standard fountain pens and some of them come in metal with a cap that can be screwed on. I wouldn't recommend the tiny converter (aka refiller) for them, however, they are hard to use without getting ink on your hands. Cartridges are better.
This story caused me to re-activate mine and a few other fountain pens I haven't used in a while.
A bit more expensive ($30), but the TWSBI Eco is excellent and highly recommended by the fountain pen community. I traded up from a Pilot Metropolitan recently and use it daily now. Lamy Safari is generally recommended as well.
Used to use Parkers and Watermans (Watermen?), got a Safari a few years ago and upgraded to a 2000 (rather more expensive piston-filler). Now I've got 3 (in a mix of nibs and stainless steel/Macrolan).
And if you want to move up toward the top of the heap without totally breaking the bank a Lamy 2000 is worth checking out. Great nib out of the box, but can be tuned to perfection for a bit more $$.
For real inexpensive, try a Jinhao x750. I have one with a Fine nib and with that single pen I can get every width represented in a set of Micron technical pens. Currently using a bottle of Parker Quink from my local Staples. Addictive hobby!
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.