When I checked online printing services the last time, they were really expensive. For my very first project (4 custom card organizers) it would have cost me more than a hundred bucks. My printer + the initial accessoires were around than 200 bucks and I've printed so many functional parts since then that it easily amortized itself within the first year.
I can't think of any printers that would get smaller if you could slightly disassemble them. They would all take a lot of disassembly, and then still take up almost as much space as before.
I like the idea of just using a print service. More expensive per print, but if you don't print often, it's probably cheaper than buying and maintaining your own.
I own an Ender 3 V2 that I use around 10 times a year. It is one of the less sophisticated printers and still it does not require that much maintenance. You have to remove the dust, level the bed and sometimes clean or exchange the nozzle. More sophisticated printers can also do some stuff automatically (e.g. the bed leveling part).
However, the initial assembly and fine tuning took some time (approx. 1-2 hours), so I wouldn't recommend to dis- and reassemble it all the time. If you don't have that much space, maybe check for a small printer.
When I did my research 2 years ago the Prusa Mini was quite popular for small printer. But if you want to print big parts a lot, it might be a bit annoying as you always have to cut them into smaller chunks, print separate and finally glue them together.
How "not use it very often" are we talking about?
The critical thing for any printer is first and foremost bed leveling.
If you get something like an MP select mini The footprint is about 30cm^3.
You can absolutely throw it in a box and just pull it out whenever BUT you will need about 30 minutes to relevel the bed just perfect and potentially run a test print.
That said, this machine also only prints a 10cm^3 and it will handle PETG IF it's been modded otherwise it's PLA and that's it.
Which segue nicely into my next question:
What will you be printing?
Models and minis?
Functional parts?
Random statues you find online of waifus? (Only slightly kidding)
This matters a LOT.
For the first: The mini will sorta work but not be great with details.
Fort the second plan on a printer that can handle PETG at least.
For the latter, you want to look into a resin printer. They WILL fit into a closet when emptied and cleaned BUT the cleaning process is both lengthy, tedious and potentially noxious and requires quite a bit of space so I didn't even mention them in the first part.
Most of my current printing needs would be small-ish structural parts. Maybe brackets for mounting something into a weird place, cases for microcontrollers,... that kind of stuff.
Look at the bambu a1 or a1 mini. It seems very easy to print woth and a lot of things like bed leveling are automatic on it. Its also starts at $300 and $400
Sorry about the late response, OK, brackets and cases for microcontrollers are actually great on a select mini. I agree with others that a Bambu would serve you great AND give you MUCH better finish etc... but the footprint of that thing is about twice that of the mini.
I know of at least two prototype printers that are smaller BUT they are prototypes with all the faff that involves including troubleshooting them every time you move them.
If you're going to move it, whatever you get, makes sure it has auto bed leveling. Fucking around with that kills the spontaneity every time. I move around an Ender3 V2 with the BLTouch leveler all the time, carrying it with me back and forth from the farm to the city. I plunk it down and it sorts itself out easily.
Stick to a cartesian style though, I have a delta I built and even with bed leveling, it gets out of calibration if I move it.
Idunno why you would want a 3d printer for a print here and there. Most of the fun with 3d printing comes with the printer itself. Hot end gets clogged, bed adhesion problems, levelling problems, diagnosing and going overboard on a simple fix, that what the fun is all about.
From my experience it's definitely not as bad as described there. Yes, there are some issues here and there but still a 3D printer is an awesome tool to have at hand. I often designed / printed spare parts and fixing something on a Sunday afternoon spontaneously. Without much planning and lead times, without a third party printing service. Feels pretty awesome.
I would say in 8 out of 10 times I can just plug the printer and start using it without issues. In 1 out of 10, I have to do some small tweaks (e.g. bed leveling for 5 minutes) and in maybe 1 out of 10 I have to invest a bit more time for leveling or unclogging the nozzle. But even all that is less than 30 minutes.
Fixing the printer is nothing that I enjoy but using it is so handy that it definitely makes up for the small hassle here and there.