Example, this #SingSang #ShuffleBook with #lullabies and other #childrensSongs: https://mastodon.social/media/j69r1RO5QSDDHohpMzs
It had nice drawings and lyrics to various songs, but for the 'gratis soundfiles', you have to visit a website, www.singsang.com, which of course is no longer available: https://mastodon.social/media/KjMmbe6HJKPtp7xGp6U
This product is ©2014, and while I bought it #secondHand (and was already expecting the website to be dead), it's still being sold full-price in retail stores.

