Plenty pepper and chadon beni, no sweet mango or anything that kills the pepper. Don't drink anything either - makes my mouth stop burning from the pepper. This from a husband/wife team who sells outside their house on Real Street in San Juan.
Other than them, I would buy from the guys on Chacon St. (family)
Dee Balos - Croisee, Park St. and Charlotte St.
UWI - used to live off that went I was there.