Following the Summer Games event in Overwatch, Blizzard made the choice to let players use in-game credits to buy the unlockables they didn’t get randomly from loot boxes.
You can’t buy this credit with real money. It’s only earned in loot box drops, whether through credits dropping alone or duplicate items dropping.
Folks on Reddit have been keeping a running tally of how much in-game money it would take to scoop up all the items in each event. The most expensive before this one? Year of the Rooster. If you wanted to buy all 99 items with credits, it would cost you 37,050 Overbucks.
The Anniversary Event? If you wanted all 108 items (including 11 Legendary skins and 24 dance emotes), you’d need to drop 56,475 credits to do so. That ain’t cheap.
Of course, I don’t think you should drop all those credits right away. What I always do is this: I play without buying anything until the last day of the event. I hope that I get lucky and see all the stuff I want drop through loot boxes. If it does, cool, less credits I have to spend.
If I buy something early and that same thing drops before the event is over, the duplicate isn’t worth the same amount of credits that I spent initially. So, I hold my money until the end of the event, then I go nuts.
Besides that, you just keep playing, complete all the arcade stuff for free loot boxes and level up as much as possible.
The Anniversary Event runs until June 12, 2017.