right now, my main strategy is to grab the harder to fetch items.

The rarest of the Takara's include:
#00 Prime (no clue where to purchase)
#06 Megatron
#09 Starscream
#10 Soundwave
#12 Minibots

The very difficult to find include:
#11 Astrotrain
#16 Insecticons
#17 Blitzwing
#18 Soundblaster

The up and comers, keep your eye on these:
#07 Sideswipe
#13 Hotrod
#14 Hound

I really want a #07 next