First of all, never send post cards without envelopes. Post cards are sold here WITH envelopes. They get lost without envelopes. Take your post cards to the most reliable PO, the CENTRAL POST OFFICE on Alem. It´s a beautiful, imposing building that has a little museum inside worth seeing. There is also a special philately section as you enter to the left of the hall. They sell all kinds of special stamps. The post office was state run when I came here. Then it was privatized and service got better. It has since been re-nationalized and prices have SOARED and service is worse. Despite this reality, a lot of people here persist in thinking that state owned services are better and help the people. Not the case with Correo Argentino.