Shell Spiffy is a magazine that only appears in the episode, "Shell Shocked."
On the cover, there is a purple snail with a pink cone shaped shell that has a shiny gem on it and also shows the name of the magazine in red. SpongeBob thought their prices were outrageous - in the magazine, there is a shell exactly like Gary's shell that cost $9,595.95 or more plus tax.
Role in the episode
Gary shows SpongeBob this magazine with the intent of SpongeBob ordering a new shell after SpongeBob accidentally breaks Gary's shell.
The German title for the magazine is "Das Schicke Schneckenhaus," which translates in English to "Send the shell."