it depends on the project etc.
1) what thickness/height of the PE parts do you envisage?
2) do you want acid-etch relief stuff too?
2)b are you looking for 'hologram-lenticular etching on your P.E. ?"/ scintilated patination for use as hologram/micro-stanhope?
3) what detail is needed/ how do you feel about ablation etc?
3b) where you're etching onto embossed foil etc, how do you feel about ablation potentials
Lazer-etching laminated stuff and architectural decals can get fun too.
Depending on your answers to those -
there are potentially many
options near you.
3DMakeHubs, <--- above and beyond the more awesome option.
your local "community mates shed", and or once-off runs etc.
I get most of my 'average' grade PE from 3DMakeHubs and locals, I supply the materials to be cut.
It's usually thinned tin from fudge-trays or that hi-brass stuff "brass amalgam". (Range brass has a use after all!)
and, CNC'd vinyl, or lazer-etched APEC-5
Of course, the options become trickier if you're wanting microPCB/flexi-PCB rap-fab etc
for that kinda 'durable prototype homemade PCB" end,
you need more like the Xerox rap-fab machine.