Incense in Pokémon Go is used to attract Pokémon to the player using the incense. It stacks with the lure module if one has been placed and is best used when walking. Although, you can catch Pokémon without movement you’ll only attract 1 every 5 minutes or so. If using an incense while walking you’ll attract 1 Pokémon per minute for every 200 meters or .125 miles. An incense does not attract Pokémon on your radar to you but rather new Pokémon to your area.
To gain the full advantages of an incense use it in conjunction with a lucky egg for double the XP. Incense can be purchased through the shop store via pokecoins and cost 80 pokecoins for 1, 500 pokecoins for 8, and 1250 pokecoins for 25.
You also receive incense for leveling up. Level 5 rewards 1, level 7 rewards 1, Level 10 rewards 1, Level 15 rewards 1, and level 20 rewards 2.