Our playgroup only runs 5 sessions a week - 2 on Mon and Fri and one on Wed morning.
We charge £6.50 a session for non-funded children, nothing for those who are funded. Sessions are 2 1/2 hours each, and we also offer a lunchtime session of 45 minutes for which we charge an extra £2. This bridges the gap between morning and afternoon sessions, so parents could have 9-3 on Mon and Fri.
It's strictly first come first served here, no other admissions policy. And I do let people 'reserve' spaces so that for example their child can start off with a couple of sessions, then book extra sessions for later on.
Schools round here only have one intake, so what we find is we're always full in the summer term, then all the 4 year olds leave for school so we have a quieter term or so until it picks up again.
We normally take children from the start of the term in which they're 3, but on an individual basis (and especially if we're short on children!) we will take them from 2 1/2.
We let parents have as few or as many sessions as they want - some do all 5, others only do 1 and some do a couple with us and one or more sessions elsewhere.
As for fundraising, we don't actually do much. We're a bit different because we're a church-run group and heavily subsidised by the church (we only have to make donations for use of hall etc, rather than pay proper rent).
This also means our committee is a bit different - our constitution says the chair and treasurer and secretary must be members of our church, so it's not as parent-led as other committees, although we do make sure we have parents on board.
It's a lot different to the committee I used to be on!