Seals

While leveling, you will regularly gain Seals of the Adventurer. You can exchange these seals in Protector's Enclave, either on the Market Place or in the Adventurer's Guild, to the Adventurer Seal Trader. There are Adventure Seal Traders in many other places too. Your seals can be exchanged for 950-1000 item level gear for any of your characters, for 250 seals each.

Main Hand and Off-Hand Weapons, Shirt, Trousers, and Rings, are Bound to Account (so you can give them to new characters, for a total of 5950 item level, to make their leveling a bit easier). Head, Armor, Arms, and Feet are Bound to Character though, so you'll have to get them while leveling. They do not have level requirements.

Assuming you stick with the quests and didn't miss any seal, you can buy your first piece in Vellosk, after completing the Sacred Meeting quest. You can buy your second piece after completing Moonlight & Shadows in Vellosk. You can buy your third piece after you complete The Throne of Idriss in Ebon Downs. You can buy your 4th piece after completing An Axe Too Far in Icespire Peak. You can buy your 5th piece after Icespire's Frozen Heart in Icespire Peak. You can buy you 6th piece after completing Chasm Report (back to Sergeant Knox after The Chasm). You can buy your 7th piece after completing Back to the Surface (back to Sergeant Knox after completing The Whispering Caverns). And then you'll be level 20 with other ways to gain seals and better items to look for.

Later, if you do not know what to do with your seals, you can get 500 RAD for 500 seals. Not much, but better than nothing.