Where can you buy beans for a bean bag in Montevideo?

It seemed to me that all 'bean' bags in Uruguay were actually filled with foam chips so I went on a mission to find actual beans to fill my bags. After much searching I managed to find bags of beans at a shop called Paganini Rossi, address: Colonia 2223 (not too far from Tres Cruces Mall area). 350pesos for a large bag (1kg worth). However, I made the bean bags myself because to find those is much harder - unless you like plastic/vinyl covered bags which seem to be able to be bought in Uruguay (but are not very comfortable to sit on).  It took me two 1kg bags of beans to fill each of my bean bags.