The inventory offers a variety of hat options, whether it be from the Battle Pass, Special Offers or Clan quest items however there are plenty of purchasable hats too straight from the inventory, some cost more than others depending on the rarity, these hats can also be won in the Loot Box.
Rose Hats
There are also special hats that can be bought with roses (75-150) once reached a certain level.
Secret Hats
Secrets hats can be found by unlocking easter eggs, or spinning the rose wheel
You can also get one by inviting a friend (the invited friend gets an umbrella hat!).