5 euros for the pearl clay at Flying Tiger.
It needs good kneading and mixing for the pearls not to detach, it sun-dries within from a few hours to a day, and this Italian blog explains more on how to use it:
My first project is going to be a Tyrell or Martell smartphone case... inspired by this Swedish YouTuber's pineapple:
This summer, I will hopefully also get the colour-changing duckies for my footbath.
These ducks change colour in hot water and change back after a while in the fridge.