The central and most popular shopping district for Santiago [1] is along Calle del Sol. It is a great way to feel the commerce-culture of Santiago and get a feel for this city. Simply strolling along this busy street, you’ll find many small stores, vendors, and hawkers.
Much like the Mercado Modelo in Santo Domingo [2], there is a lot to pick from at Mercado Modelo (Calle del Sol, 9 a.m.–5 p.m. Mon.–Sat.): knickknacks, souvenirs, Haitian paintings, jewelry, and all sort of other things to set yourself to haggling over. That is half the fun anyway.
Since you’re in the region of serious tobacco production, it would be wise to make your cigar purchases here. At Centro León [3] (Av. 27 de Febrero 146, Villa Progreso, tel. 809/582-2315, fax 809/724-7644, 10 a.m.–7 p.m. Tues.–Sun.) you can not only watch the rollers at work, you can buy some of the world’s best cigars.
Links:
[1] http://www.moon.com/destinations/dominican-republic/el-cibao/santiago
[2] http://www.moon.com/destinations/dominican-republic/santo-domingo/shopping
[3] http://www.moon.com/destinations/dominican-republic/el-cibao/santiago/sights/centro-leon