We used the Fleadh campsite last year in Ennis. Clarecastle GAA.
We booked 3 nights - I dont remember any talk about minimum nights.
Free frequent shuttle bus all day long ( ? 1130pm last bus) in and out as many times as you want. Dropped you in centre of town.
Very well organised campsite, plenty big marked pitches.
Late clubhouse bar, takeaway vans, showers, service point for grey and black water.
I thought it was excellent value and I am a compulsive wild camper.