Buy them from general goods merchants
Buy them from fences and thieves guild merchants
Pickpocket them from NPCs
Loot them from bandits, thieves, and dead bodies
Find them in barrels, crates, and chests
Steal them from shops and houses
Receive them as quest rewards
Get them from the Dark Brotherhood sanctuary
Obtain them from the Shady Sam merchant outside Imperial City
Use console commands on PC if needed