Are you sure it was Toro? Masa (also in the south end, but Mexican, not Spanish) has in the past offered 50 cent 'tapas' on Sundays, Mondays, and Wednesdays . Assuming they still do it, but not sure.
I'm not sure - this info comes from a friend who has a friend who used to hostess at toro, presumably. But perhaps it was Masa...that's the problem with third-hand sources.