Wikia

Non-Members are penguins that do not pay a subscribed Membership, or former members who had a membership that expired on Club Penguin.

What Non-Members Can DoEdit

Buy colors, flags, and backgrounds from catalogs, and most recently are able to buy items from a page in the Penguin Style catalog (introduced in January 2013).
Collect a free item given away at a parties, become an EPF Agent, Ninjas and tour guides.
Wear pins, found hidden on the Island.
Buy up to two Puffles (two Blue Puffles, two Red Puffles, or one of each color).
Buy puffle food.
Waddle around anywhere in Club Penguin, excluding "member-only" rooms (certain Party rooms, the Underwater Room, and the Cloud Forest).
Chat with other penguins.
Play certain levels in most mini-games.
Earn stamps, excluding member stamps.
Meet Famous Penguins and obtain Autographed Backgrounds.
Unlock items or puffles from the Treasure Book.
Decorate their igloos with certain furniture items.

Buy furniture.
Buy any color Puffle apart from the Red Puffle or the Blue Puffle. However, they can get any color of Puffles if they have a toy code.
Open their igloos to guests.
Obtain stamps that require membership.
Buy most clothes or objects.
Obtain member-only pins like the Moss Key Pin.
Buy or obtain member backgrounds like the Coral Reef Background.
Play certain levels of games like Catchin' Waves and Jet Pack Adventure.
Enter member-only rooms.

Many new non-members seem to be usually seen waddling around wearing Card-Jitsu Belts, the New Player Red Baseball Hat and the Amulet.
There are several catalogs with items that non-members can buy as well.
Non-members can unlock the Pineapple Igloo via Innocent Smoothie codes.
Penguins can still keep their puffles, member-only stamps and pins, and the elements on the Amulet when their membership have expired. However, they cannot have access to the members-only clothing, igloo and member-only furniture, their decorated stamp book cover, etc.
When a membership expires and the penguin is wearing member clothing, it stays on.
Prior to February 2010, flags could only be purchased by members.
As of January 2013, non-members can buy clothing in Penguin Style.