Seine-Saint-Denis has two of the major exhibition centers in the Parisian region : the exhibition centers of Villepinte and Le Bourget, a few steps away from Seine-saint-Denis in the 19th district of Paris there's the La Villette park with its Grande Halle, perfect for exhibitions and fairs. Major exhibitions for the public such as Japan Expo, international fairs are held all year round such as SIAE in le Bourget. There are many accommodation options near these exhibition centers so you can come and go easily.
The towns in Seine-Saint-Denis often organize garage sales and flea markets for those who love bargain hunting. Bargain hunters can't miss the two major markets in Paris : the Montreuil flea market and the famous Saint-Ouen flea market.