[Crazy Jetty]

Scale? What's that?
Something no one's mentioned yet for you, is "class" like Scouts, are pricepoint sizes.

First are Minicons. None are sold anymore by themselves, but originally they were tiny, and in three-packs, and connected to large TFs.
Next up are Scout Class. They average $8.
Deluxe follows, at roughtly $12. (Generations so far is exclusively deluxe class line)
Voyager Class, is when TFs start being in boxes, and average $20.
Ultra Class (There are currently no ultras at retail), $30
Leader Class, $40
and Supreme Class, $50 (Typically. However, RotF Devestator was called Supreme, and was $100. Battle Opts Bumblebee is claimed to be a Supreme, and is $60)

Outside of the main line, are the Legends, and the Power Core Combiners.
Legends are the smallest, they average $5 usd. Think of them as pocket transformers. They're really sort of a sidesomething that's entirely all to themselves. They're roughly to TFs, what DCIH is to DCUC.

Powercore Combiners are a second sideline that Hasbro hasn't really given an official home to. They come in two pricepoints, and you'll find modern Minicons with them.

2-Packs, $10
5-Packs are $20.

Minibots are a fan term for a specific group of G1 transformers that were released in 84, 85, and 86. They were a group of small transformer toys called Minibots, and fans still use this term to carry over to the same characters (Such as Bumblebee, Cliffjumper, Brawn, Cosmos, Wheelie, Warpath, Powerglide, ect) for *any* release, no matter how big or small. So try not to let that confuse you.

And so, if you're trying to keep things in scale, good luck. There pretty much is no scale in TF.

Legends are generally not in scale with anything at all.

For scale, here's the closest thing:
Movie Universe Autobots:
RotF Leaderclass: Optimus Prime
Movie 1 Voyager: Ironhide, and Ratchet
Movie 1 Deluxe: Jazz
HftD Deluxe: Battle Blades Bumblebee
RotF Deluxe: Mudflap, Skids, Sideswipe, Jolt
RotF Legends: Arcee, Wheelie

It's not as accurate, but a second line up at a smaller and cheaper scale-
HftD Voyager: Battle Blades Prime
HftD Deluxe: Irohide, and Ratchet
RotF Legends: Bumblebee, Arcee, Mudflap, Skids, Jolt, Sideswipe.

The Decepticons have very little scale with each other, and NO scale with the autobots.

Hasbro is inconsistant with scale. Back in the day, we had motorcycles the same size as space shuttles.
Flash foreward to now, again they're still inconsistant. Blackout, who's one of the biggest characters in the movie, is actually shorter in stature (Dispite being a voyager) than Arcee (Who's a deluxe).
Then they also have stated that Generations will be exclusively Deluxe, which means that all characters, no matter how big or small they originally were, are equal.