OH ... btw ... that Kup / Stepper /Hotrod deal is very good ... but those are the most common TFC's around. It's not very hard to find those at all.

There is a definite order you should pick these up in.

Hardest to find
#00 Optimus Prime
#06 Megatron
#09 Starscream
#10 Soundwave
#12 Minibots
#18 Soundblaster

Getting hard to find
#01 Jazz
#07 Sideswipe
#14 Hound
#16 Insecticons
#17 Blitzwing

They're out there ... but you gotta look
#02 Prowl
#03 Skids
#04 Tracks
#05 Smokescreen
#11 Astrotrain
#19 Perceptor

You'll see these all the time
#08 Inferno
#13 Hotrod
#15 Stepper
#20 Kup & Wheelie