Every neck is different, but in general the PBG necks are pretty player ready. That's not to say that you'll never get one with some sharp fret ends or a high or low fret.
Unfortunately as I've said, nut files are rather expensive. I'm assuming we are talking guitar here (bass is easier as you can simply use the end of a round needle file). If you use 9s or 10s, then this is probably the cheapest decent set of files I've come across: http://www.axecaster.co.uk/index.php...roducts_id=302
They are not quite as good as the individual nut files that Hosco make as you end up with more of a 'v' groove in the nut rather than a straight slot, but they still work OK.
There are also these from Crimson guitars: https://crimsonguitars.com/store/nut...g-file-blades/ I've not used these before, but I did have a similar looking set from the US which were OK, though each one was a bit different in performance - what took two strokes on one might take 10 on another. Whether these would be the same I can't tell, but the benefits are a fairly low cost and you've got more size selection.
This is the set I bought and am really happy with. They cost a bit less a few months ago, but that's the falling £ for you. https://tonetechluthiersupplies.co.u...set-of-10.html
They all seem to have the same level of sharpness, which makes it easier to gauge how much filing is required to achieve a certain depth.