I don't shop at Sainsbury's either. Where I shop, (Morrisons) they are one pound forty nine for one regular can and .50p for a half sized can. (btw this is an American laptop and doesn't have a pound sign on it).
Maybe I am a cheapskate, but the larger can is over priced and the smaller can is overpriced but not as much as the larger can.
I could do with a bit more than the smaller can, but can't finish the whole large can, which I think is really a waste.
There are only two of us.