Try the pet shops. There is a pet shop in almost every town on Horse Isle. The pet shop with the most ferrets I've seen, though, is the Pet Shop in Hotton on Desert Isle.
Water wings are not available for ferrets as they are not swimmers (though they can swim)
Wington food store =)
You can buy tham at Earton General Store :)
Wington Tack Shop
You either have to grow it on your ranch or buy it.
Treeton Pet Store for $3,000.
Check your local pet stores
you can not own ferrets in California, so you can not buy them there either.
you can buy a guest book in the tool shop
the tool shop on tiger isle has it.
you can buy one at the tool shop
Joylyn in treeton will buy your unwanted grasshoppers.