I've just bought a pack from Aldi today for the same reason
. We're going on hols abroad and won't have access to a washing machine and have limited bagage allowance so no cloth for a week
I bought size 4's but erred on the large side as I'm hoping they'll last for longer (emergencies/grandma etc). Nell fits on the middle snaps of BBSS's so I would've though size 3 would fit Summer (but 4's prob ok too).