When it comes to old PPVs, pawn shops, garages sales, and flea markets are your best friends. Also, some of the old independant video stores may sell them. There's one in my ex girlfriend's old neighbourhood that rents them or sells them, along with dusty old NES games, too. Yes, seriously.
Edge's injuries are par for anyone at this level. Cena, HHH, etc. have all had their share of injuries in past that have kept them out of action. Plus he's a proven superstar and not a one-trick pony like Kennedy (mic) or Batista (big muscles)