Managua has two main markets: the Huembes market and the Oriental market. Although Huembes is considered by locals to be the "tourist" market, I'd actually recommend it over Oriental because it's safer, easier to get around, less chaotic, and (as a traveller) you'll probably find more of what you're looking for. Yes, if you want everyday stuff (shoes, electronics, whatever), Oriental is slightly cheaper. But if you're looking for souvenirs, gifts to bring home, handmade clothes and jewelry, leather items, furniture, hammocks -- pretty much anything artisanal -- this is the place. The market also has a large produce section, where you can buy all sorts of local fruits and vegetables you've never tried (much less heard of!) before. Make a whole morning of it: do your shopping, then have lunch and a refreshing Coke drunk from a plastic bag with a straw, Nica style, at one of the market's many food and drink stalls.