A really good place for spices and nuts (VERY low prices) and good quality, is "Bombonería Royal". It's a big candy, wine and gift shop at Lavalle 951 (peatonal),between Carlos Pellegrini (9 de Julio) & Suipacha, about 1 block from the Obelisco. It looks like a big candy store but all the way in the back they sell many items in bulk, and you will be surprised at the low prices. I buy pepper (for grinding), garlic, parsley, hot pepper flakes, oregano, basil, walnuts, prunes, peanuts and sesame seeds there. I have never found lower prices anywhere else.