I have 2 yellow diapers for the 2 Snoozy variations I paid around $15-20 for each one. Out of the 3 babies in that set, Snoozy is in the middle rarity-wise with Cuddles (green diaper) being the most common & Bouncy (pink diaper) being the most hard to find.
The one tricky thing with these diapers is that Hasbro made a very similar diaper in the same fabric sold with their Drink & Wet Puppy Surprise in the early-mid 90's, as well. I was mistakenly sold a diaper from that set labeled as one of the Surprise Newborn diapers.
Surprise Newborn Pony diapers have stitched sides (hip area) & velcro at the tail. Puppy Surprise diapers have velcro on each side/hip, and no tail hole.