@ajroach42 That's how it starts
I mostly buy new because vintage is a minefield
If you're after a mechanical watch then Seiko is a good start, the Seiko SNK809 is pretty much everyone's first automatic, they're great value and you can find them for £70-80
Or if you want a dive watch there's the SKX007 which is about 200 quid, fully rated for diving, and in my opinion looks pretty damn nice
See, I'm fairly certain that I wouldn't even check a mechanical watch if I wore one, so weather it works or not would be kind of unimportant.
OTOH...
@ajroach42 Oh yeah, the SNK809 has a clear caseback so you can see the movement from the back, that'll get you hooked if nothing else will seeing all those little gears moving around
@ajroach42 digital watches are still good, casio actually still makes a bunch of their more retro designs, might be worth looking at those