I was searching around and just found a site that has a bunch of cool shells for cheap. Some are suitable for hermits, and some not. Many shells are sold for pennies each, some of the smaller ones by the pound. Almost all are cheaper and nicer than any I've see from fish stores, on- and offline.
http://www.shells-of-aquarius.com/
They're web site is a little hard to navigate, but it has pictures and descriptions of about everything.
I'm thinking of placing an order. Here are the ones I like for hermits:
ONE HAND SELECTED BABYLON JAPONICA SHELL 1 1/4 to 1 1/2 inch
One Cancellaria Shell 1 to 1 1/4 inch
ONE CYMATIUM SARLOSTOMA SHELL 1/2 to 1 inch
ONE DISTORSIOS RETICULATA SHELLS 1 inch or less
One Latrius Gibbucus Shell 3/4 inch or less
ONE BROWN MARGINELLAS SHELL 1 inch or less
ONE TAN MARGINELLAS SHELL 1 inche or less
ONE BAILER MELON SHELL 1 1/2 to 2 inch
ONE QUARTER POUND OF NASSA PERSICA SHELLS 1/4 inch or less
ONE NAUTICA LINEATA SHELL 1 inch or less
ONE White Nautica SHELL 1 inch or less
One half pound of Common Nutmeg Shells 1/2 inch or less
ONE PEARL CINERIUS SHELL 1 1/2 inch or less
ONE QUARTER POUND PLANAXIS SHELLS 1/2 inch or less
ONE HAITION TREE SNAIL 1 to 2 inch
ONE BROWN LAND SNAIL SHELLS 1 to 1 1/2 inches
ONE HELIACUS SNAIL SHELLS 1/2 inch
ONE BEE HIVE SNAIL SHELL 1/2 inch or less
ONE STRAWBERRY CUMINGI SHELL 1/2 inch or less
ONE HALF POUND OF BLACK UMBONIUM SHELLS 1/2 inch or less
ONE WHITE CORNBALL SHELL 3/4 to 1 inch