Save your Titan. You don't need to use your Titan or upgrade your equipment rarity to Purple or Exotic until you are level 30. You'll be changing items often enough anyway, and you can definitely save the Titan for later to upgrade the good items.
At the beginning the items all cost leather or iron, but from the rarity "Purple" on the cost increases to titanium and later on landing capsules:
If you apply your titanium to the items while you're already leveling up, once it's important you won't be able to use it to raise your exp level.
Therefore, save your titanium at the beginning, you can't use it wisely anyway, because you don't have the right item level yet.
Trick: Keep only blue equipment as long as you can, because you can easily level it up until you are level 50 and then increase the rarity of the item. This will save you a lot of resources. It is always cheaper to level up a blue item than an epic or legendary item.
Until you are level 30, try to increase your world level regularly. The easiest way to do this is to replay missions that bring a lot of XP. This will give you access to level 43 equipment and make it easier to start expeditions. How to replay expeditions and which ones are best for you can be found in this guide.
You can increase your expedition level by completing expeditions at silver level or higher. To reach the highest level (CT/RT 15), you must complete an expedition on difficulty 14 with a Gold achievement.
Once you reach expedition level 15, you can play the Eye of the Storm expedition and experience the actual end of the Outriders story.
Of course, you can get Legendary and Epic items from expeditions.
The more difficult the expedition, the higher the chance of getting Legendary Items.
However, there is another way to get Legendary Items, where you even have a 100% chance of getting a Legendary Item.
The bounty and hunting missions can be restarted at any time in the bar in Trench Town.
For each completed mission you will receive a random epic item. Once you have restarted all missions, you will receive a guaranteed Legendary Item.
Every 30 minutes to an hour the offers of the dealers update and especially when it comes to the perfect equipment, it is recommended to check the offers every now and then.
There are dealers in the following cities:
In Rift Town, the dealers are located right next to each other. If you only have one of them, you still have to complete the quest behind the door in the middle of the two stores. After that you can also use the weapon store.
In Trench - Town there are also 2 merchants, you can find one right behind you when you travel to Trench-Town. His name is "Hard Pavlo" and he offers clothes.
The second one is called Eryk Rib and you can find him on the way to the bar, he offers you weapons.
Last but not least, there is Mercer Acosta in the Forest Enclave he also offers you a fun side mission and is not marked as a merchant on the mini-map.