How to Unlock Unlimited Fast Travel in Horizon Zero Dawn:

Step 1: Get Rare Fox Skin & Fatty Meat by hunting foxes. Press R3 to scan your surroundings for animals. It takes 5-10 fox kills for it to drop. They are often in woods (green areas on map).
Step 2: Buy the Golden Fast Travel Pack from the Hunting Goods Merchant in Meridian City. It costs 50 Metal Shards, 1 Fox Skin and 10 Fatty Meat. It's in the resources tab of the merchant.

Now you do not have to craft normal fast travel packs anymore. Every campfire that was previously discovered is available for fast travel. The Golden Fast Travel Pack consumes 1 resource item slot. Just keep it in your inventory and all your travels will be free. This saves a lot of time over the course of the game.

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