You can browse the exhibits at Dankwarderode Castle, a museum with a storied past, during your trip to Braunschweig. While in the area, you can find time to visit its shops.
If you like haggling for the best price, you might want to head out to Braunschweig Farmers Market in Braunschweig City Center and take in the atmosphere. Splash some more cash at Schloss Arkaden Braunschweig and Altstadtmarkt.