Keep an eye out at Hom Market — you're sure to find some treasure or trinket in one of its many stalls. After you've admired the wares, try some fare from one of the food vendors.
To visit this community marketplace, you'll need to find your way to Hai Ba Trung. You'll find plenty of other things to see in this area, like Hoan Kiem Lake, Thang Long Water Puppet Theatre, and Temple of Literature.