Keep your eyes peeled at Mercado Artesanías — you're sure to come across 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 explore this community marketplace, make tracks to Masaya. You'll find loads of other worthwhile attractions in the area, like Masaya Volcano National Park, Masaya Old Market, and San Sebastian Church.