Your first purchase in this game

Hi! It's been two or three weeks I'm into this game. Loving it. They got me good.

I'm about to purchase the First recharge soon for Bugs (hopefully) and got 6k diamonds now with 34 chance to roll the character in the event.

Curious to see if you guys remember what was your first purchase in this game and when you did it (first week, three weeks, etc.)