What are the "must buy" Premium items.
I saved my donuts for a while and have accumulated around 900 at this point. While I'm saving 525 for the previous presidents I missed in the 4th of July MysteryBox (7x75 if the price is accurate)...
Forum Discussion
I say Otto is one of the must haves. The other suggestions are great as well. Use "The Vault" and Event mystery boxes for premium discounts too.
