Begin the Shopping Spree Level. Head into the garden supply section. Pickup a propane tank from one of the shelves on the left and throw it.

Note: The object does not have to hit a player.

Finish the Neighborhood Stroller Race, then walk into one of the two large rocks on either side of the finish line.

Begin the Penny Pincher level as a child. Make your way to the laundry room, and crawl through the air vent.

Note: As long as one of the NPC crawl through the tunnel during a game of Penny Pincher, you will gain the achievement. It can be obtained solo.