Teamcoach cards have never particularly held their value. By the end of a season you can generally buy most cards for 50% or less of their starting value.
Perhaps it is a different if you are after Richmond or Collingwood cards, but I pay $2 or less for Melbourne inserts and would expect to be paying $15 or less for wildcards.
I don't think one series is more valuable than any other, at least not in the past decade.