So it seems that $18 is the min. price that retailers ought to be charging? I feel a bit better now paying $15 for Deluxe DOTM Optimus Prime at Big W But of course, not so good for all the number of times I've paid $30 for so many other Deluxes. :/

$25 seems an okay price to pay - it's outside of that "cheapest retail" range and on the lower end of "high end retail". Big W's slated $23.88 RRP for TFP Deluxes doesn't seem too bad either considering (it would place it on the upper end of "cheapest retail"). I'd be curious to see how this comparison would look for Voyagers and Leaders as I suspect that it is in these larger classes that we're getting more seriously ripped.