About how to get certain items...

BeautyStitches

I wish it was made a bit more clear on how to get certain items, especially event items. I went to Toma's event and saw something I wanted. I need LaTale gift certificates, though. Sadly, I haven't the slightest clue where to get them. Do I have to defeat particular monsters? Is it tied to a specific event? Are there any quests I must complete?