Inventory Space

Hey guys, new player here. I heard buying inventory slots for bag and bank from crown store is a newbie misake. however im level 20 and im struggling to pay that much gold to expand my inventories. Am i doing something wrong? where can i farm gold as a low level beginner player? I am doing my daily dungeons and battle grounds. i also buy the inventory capacity from the stable master.

my inventory slots are filled with purple potions and xp boosters from level up rewards. they are also filled with weapons and armor for researching. I also have some gifts from quests i think im not sure that i am keeping to open them up after i reach higher level to get better gear. Any help is appreciated! Thank you in advance!