Do yoiu mean a wrap out of the supermarket that youre gonna fill yourself, or a pre-filled one?
The wrap itself will be 1 syn per 20 calories as theres no free food. The lowest syn one I know that is of a sane size of is the Weight Watchers one which is 5 syns. There are lower ones but theyre tiny, not much use for a real wrap. Most of them are around 7-10 syns.