I have found modest size rolls of Parafilm sold as grafting tape in some
on-line/mail order growers supply places, inch and half-inch widths by 90
feet rolls, sometimes $2 for the 1/2 inch width--plus postage etc of course. http://www.orchardvalleysupply.com/ovsstore/pc/viewPrd.asp?idproduct=278
I have been using cheap masking tape for whip and tongue grafts, either 1/2
wide, or I cut wider pieces into narrower strips. I usually slit the tape by
midsummer after growth has taken off.