Midoco is a pretty rad shop full of all sorts of art supplies plus office supplies, greeting cards, kids arts & craft kits and some other odds & ends.
They also carry Halloween costumes and seasonal decor items at Christmas time, Easter, Valentines Day etc.
I'm not an artist, so I cannot comment on the pricing, but the rest of the stuff appears to be fairly moderately priced.
I love bringing my niece and nephew here when they are visiting (there are not too many interesting places for kids in the Annex)
They also seem to be open very late on weeknights, which is useful when you're desperately in need of a last minute gift of card.