The absolute cheapest way is by the six month sub, this way you get a show at random each day until you have all the shows, but you don't get to pick any of the randome shows. Then if you want to (strictly your choice) you can purchase some tickets, the fifty ticket option is the cheapest offer on tickets, but you can get as many as you feel you want.
Anyway, with the sub and the tickets, you have a show every day plus you have the option of buying one of the "must have immediately" shows either from here or Deskbabes.
If one is serious about collecting a lot of ahows, seems the best way from scratch would be the sub and the fifty ticket option.