(Llanrhaedr Ym Mochnant, Denbighshire for anyone else looking)
I see why you are confused, the fees do seem to vary a lot don't they. The least anyone pays is sixpence so that is presumably the standard fee for a baptism. Whether the others are being charged according to what they can afford or whether they get more for their money is not stated. Edward Morris, Gent. on the next page pays five shillings! The total for the year, two pounds three shillings and sixpence, is labelled 'Obl.' which I guess to be some form of Obligato?
I have now seen Andrew's suggestion but did not go back to see if the sums are all multiples of sixpence - I don't think they were.