I belong to a group with 14 members on a permit aircraft.
The aircraft is an L4 Cub of WW2 vintage,not fast,tandem seating ,but loads of fun.
The cost of flying is very low,£35/hr all inclusuive,and not many members fly frequently,some never,we use an internet based booking systems and the aircraft is almost always available when I want to fly.
We have just bought a spare engine and still have around £6k in the funds.
The initial cost of the share was affordable and we have an annual meeting where we decide hire cost and whether we need to put a top up in the engine fund ,usually between £100-300/annum.
There are lots of groups operating like this on permit aircraft,some with shares for sale,we don't have any at the moment and ours are usually sold to friends.
When I got my licence I did about 6 hours in the PA28-180 I learned on,then got a tailwheel endorsement and since then have only flown the Cub.
As already mentioned have a look at the PFA website.
Lister