Diagon Alley...

Diagon Alley is a special place in several of the books as it is where Harry first goes to shop for his school supplies: wand, Hedwig the owl, cloak, cauldron and books.

In later books, George and Fred Weasley drop out of Hogwarts to open up Weasley’s Wizard Wheezes, a joke shop in Diagon Alley. There were several cute displays in their windows including these puking pastilles.