Keep your eyes peeled at Urayasu Fish Market — you're likely to discover some treasure or trinket among the stalls here. After you've found the perfect souvenir, try some fare from one of the nearby food vendors.
When you've finished up at this Chiyoda community marketplace, why not check out Tokyo Skytree, Tokyo Tower, and Tokyo Imperial Palace? They're not very far from Urayasu Fish Market and also a hit with many travelers.