After Dobby brought Alistair to Diagon Alley, Alistair used his status as the young master to command Dobby not to speak of anything he was about to see, and then took the house-elf to the apothecary to buy everything he needed.
"Unicorn horn, Mooncalf tears... and a new set of potion vials. Yep, that's about it." Alistair checked the items inside his magic pouch; everything was accounted for.
"I'll take the items on this parchment, please." A familiar, cold, and rich voice spoke up.
Chapter 22