The AFL-CIO posts a boycott list on its web site.
I'd say your post goes to the difference between boycott as politics and boycott as lifestyle. Boycotts are only meaningful politically when they reflect some kind of mobilized constituency. Boycotts in terms of some global catalog of good and bad business firms is more like a personal moral expression, fine as far as it goes but not to be confused with politics. The personal is not political.
Under boycott as politics, only a few items would be legitimate targets, since politics means focus. On these terms, I would imagine that usually most folks can afford to be in the game. If not, there are always other ways they can contribute.
As for the Spice Girls, nobody has said much about the most interesting one (potentially) -- Ginger, who has left the gold mine the group had become. Not unlike Jimmy Ruffin leaving the Temptations.
MBS The Ancient One