I've no idea what the lowest syn ice lolly is, but I recently saw some Fab ice lollies in Sainsbury's, they were on offer & brought back childhood memories, so I bought some & they worked out at 5 syns per lolly which I didn't think was too bad.
I remember them as a kid (30 odd years ago lol)
Was also gonna try milk, or an options, or a yoghurt - just gonna experiment a bit and see what happens, the worst is they're horrible lol
Need to find some room in the freezer 1st