Keep your eyes peeled at Benito Juarez Market — you're likely to come across some treasure or trinket among the stalls here. After you've had a thorough browse of things, grab a bite to eat from one of the food vendors.
If you're staying a while in Oaxaca Centro, Benito Juarez Market is an interesting place to start your exploring. This community marketplace is one of many attractions that'll keep you busy here. Zocalo Square, Church of Santo Domingo de Guzman, and Auditorio Guelaguetza are also waiting to be discovered close by.