Vauxhall/Opel Corsa B-Type (MkII) would be the best car to learn servicing and repairs. Over in the UK, I could get one for about £200. They are ridiculously easy; For example, a Cylinder gasket replacement involves removing a couple of bolts, the timing and Aux' belt, a few bolts, take off a few hoses and wires and then pull the whole thing out of the engine bay. One of the easiest cars to work on for big engine jobs.
Plus, with the amount of rust these suffer with, it'll get you prepared for that side of auto-mechanics, too! ;) Plus, the filters are right in sight; You can see the air filter right there (though, it usually looks like a black box rather than this terrible, short-sighted POD filter) and the oil filter is right on the front of the engine, though I do despise these sideways-mounted filters. Fuel filter, they're usually along the frame line under the car near the fuel tank, except in the earlier models where it was on the top of the fuel tank.
And if you mess something up, who cares? It was £200, you could probably buy whatever you broke for 20 pence, lol. There are a few things to note with these vehicles, however.....
If you're COMPLETELY new to anything to do with working on cars, there are tips you need to learn with how to use your tools (quote on quote) properly, as things like not positioning your wrench or sockets properly on the bolts can easily cause permanent damage if you've not got replacements handy, simply because of the amount of rust. Also, make sure that you're fully loaded with Torx and those vile six-point sockets, or worse yet, those cursed triple-squares that you never seem to have the right size of.
If you're wanting a car that you can actually still drive, another good car would be pretty much any old 4x4 or 4x4-sized vehicle. They are remarkably easy to work on because of the amount of space, plus they don't tend to have massively complex systems. (Old is being about 1990s to early 2000s.) They are great, and if you get a Ford Ranger or Mazda B3000 like ChrisFix on YouTube, you can watch his videos and learn from him with the same vehicle he usually shows!!!! :P
Just make sure if you buy a car, you have the right tools to work on it. It's great having a massive tool set, but if you're missing a couple of little bits for things like gearbox fill and empty ports, you're a bit stuck, aintcha?
Good luck on your journey with servicing experimentationings! ;)
(Yes, disregard the spelling mistakes, it's a bit of fun on my part!)