They're scattered across the map as pick ups. Just explore the map until you find one of them, or wait for them to appear. They take a few minutes to re-appear in the map as well.
The first screenshot is from an older version of the game. Since then they've revoked the ability to purchase and use gear at any time for balancing reasons.
That's very interesting how it still has the slots for the gear on the control settings. The developers most likely just forgot to remove them.
Well. I hope the add it back some time. I don't see why they had to remove it. Why couldn't they just limit it to 5 gear purchasers per round and 2 is the max amount of a single gear item. Or even one of each
