Booster Pass

Room 1:

As soon as you enter, talk to the 2nd bush on the right. You will receive a Frog Coin.

Jump up the rocks to the top and there will be a hidden chest containing a Rock Candy.

NOTE: do not run into the bush below the Rock Candy! It is an Artichoker encounter and you can't run away. You will probably game over from the encounter as you are very underleveled.

Just leave the room and go through the next room to get to Booster Tower.

(video credit: Mill)