Morning. Do you mean an actual percolator:
Or are you saying percolator as a generic term for coffee brewer?
Actual percolators make a filter-type long coffee as opposed to the short heavy brew from espresso or stovetop (aka moka pot), and they do so by circulating boiling water repeatedly through the coffee. This isn't great for the flavour of good quality beans which is part of the reason why percolators have become pretty outdated, you'd struggle to find one other than online I would guess.
If you want an espresso type brew go for either a stovetop brewer or an actual espresso machine, though you say affordable and getting into home espresso is a bit of a money pit if you want to do it well.
My recommendation: Buy a good hand grinder (£30 - £40) and then take your pick from filter cones, aeropress, cafetierre, whatever. In my experience it doesnt matter how cheap your brewer is, just make sure you put high quality fresh beans in it. You can get something approaching espresso from an aeropress if thats what you're after.