Suggestion for a campsite - Peak district, affordable, public transportable-ish?

[CrinklyLion]

Asking on behalf of the eldest nibling (mid-20s) who is trying to win an argument against wild-camping by finding a good site that would not be too expensive, and would have a loo.

Luxury not required, but basic facilities very much desired! I think there's a few of 'em going, so a site that doesn't outright ban groups might be sensible.

Any recommendations?

[Paul H]

Peak District is a big area, any preference?
Here's a starter - Hulme End for £7 per person per night, a bit basic, toilets and sinks, groups if booked, can get a bit busy.  On a bus route, I think from Buxton.
http://www.hulme-end-campsite.co.uk/

Or for easy train access there's a couple in Edale where you can walk from the station (Sheffield > Manchester line which is worth doing for itself) I've used Fieldhead, decent facilities, a bit more regimented than Hulme, £10 a night.
https://www.fieldheadcampsite.co.uk/prices

[CrinklyLion]

I think they're mostly travelling from Sheffield...

[Paul H]

I think they're mostly travelling from Sheffield...

In which case, those close to the Sheffield > Manc railway might be ideal. 
There's plenty of choice, the only other two along there I've used were Chinley, which might be a longish walk from the station, I had a bike, I don't remember the site, just the constant rain...  And Whaley Bridge, train to New Mills and bus, followed by a long uphill walk to the site, cheap and basic, but not many level pitches. 
I know a few more a bit further South, but not easily doable on public transport.

[Lightning Phil]

Edale ones have two pubs and a cafe on the door step. Some nice hill walking as well if that’s their intention.

[CrinklyLion]

Cheers - have passed those thoughts and suggestions along

[Nutbeem]

I've stayed at Barn Farm, Birchover twice
It's a really nice & well equipped site

3 miles from Matlock, 7 miles from Bakewell. Regular Bus Services to both places from a bus stop 5 minutes walk from the campsite
Bus fares when we went (ore-covid) seemed very cheap, I presumed they were subsidised.