Make it so that the travelling merchant has a chance to sell blueprints.
Price and the chance for blueprints to spawn depends on its rarity. You can either collect the blueprints to unlock new crafting recipes, or you can deposit them for EXP. Which can be used to upgrade the Resource Capacity and Crate Capacity. This addition will make the Travelling merchant more useful. And it also makes player want to stay in the game for longer, which is great for the Developers because yk... premium payouts.

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