How about £2.50 for either of them including postage?
They're very lightly used (and definitely never pooed in)as dd was a complete wuss about going in the swimming pool, so i didn't bother for about 2 years!
CAT me if you're interested. The small one is a Floaties Aquanappy, which is basically a snug-fitting pair of waterproof pants. The larger one is made by Kooshies, and is rather more like a nappy in that it fastens with velcro either side.