The main focus at KraftyCats is fountain pens, however their older relatives can also be just as fun to use!
If you look online, you can find large selections of different dip nibs (mostly vintage) for fairly low prices. These include fine, medium, broad and stub - you can even find nibs that will write on both sides! The good thing about all these different nibs is that they are easily interchangeable if you have a nib holder. You can also pick up a nib holder (these are simply the body of the pen) online, and a basic one should be inexpensive. A vintage one with an intricate design or unusual material might set you back more, but a modern wooden one should be cheap and will be likely to work with the majority of nibs you can buy.
Using a dip pen is easy, just push the nib gently bit firmly into the open end of the holder. One it is securely in place, dip it into a bottle of ink, tapping the nib gently on the side of the bottle to remove excess (which could cause blots). After inking, you can write with the pen just as you normally would. Depending on the nib, one dip could last anywhere from one line of writing to three, maybe even more. There are several variables at play - the size of your handwriting, how large the page is and how much ink the feed absorbs, as well as the size of the nib. Also, don't apply too much pressure when writing as this could cause blots, or even damage the nib if you're not careful!
A big advantage of this sort of pen is the ease of changing the nibs. It's usually more difficult to do this with a fountain pen, and you often have to purchase whole new nib units if you want to change the size of your nib. This typically costs a fair amount of money, but vintage nibs are much more affordable and a box of them can be about £9 or so.
Like fountain pens, dip pens do require some maintenance. Many nibs are made out of steel and will rust if left in contact with water for too long. To prevent this, wash your nibs (ideally after every other use of after using an especially thick ink) and make sure that you dry them off properly to avoid any damage from corrosion. Do the same if water comes in contact with the inside of the housing in your pen, as it can also make this rust if it is made out of metal. It could potentially make wood or rubber crack and warp, so make sure everything is nice and dry!
But what advantages are there to using a dip pen, I hear you ask? I've already mentioned the financial benefits; you get to try different nibs at a fraction of the price. They can be useful in other ways too, such as for use with ink vials. If you don't want to fill a fountain pens with an ink you're not sure you like yet, you can use a dip pen to sample it. Many ink reviewers use this method as they have to deal with a lot of tiny vials, and it's much easier than constantly refilling and cleaning a fountain pen.
Lastly, if you manage to find gold nibs you could be in for a superb writing experience, especially if you're a calligrapher as many of these nibs have a lot of flex which helps to create variation in lines.
if you only ever use your pens for writing large pieces of text, investing in a dip pen probably won't interest you. for calligraphy, ink sampling and other more niche uses, it could be a worthy addition to your collection!