I just received a full sealed booster box from Games Empire and was relieved to find an Omega Supreme shipped with it. I'm not entirely sure what I expected out of it, but was disappointed with how many of the foil character cards were duplicates. I was only able to make one full combiner set (Superion) though I have 2x Dreadwing combo pair.
I've just looked up a list of all cards
https://transformers.hasbro.com/en-a...game/combiners
and was pleased to see that I received a SuperRare card (King Starscream). But as they're not guaranteed one per booster (as Griffin found) its going to be darn expensive to complete the set. I think I'd have to buy at least 3-4 more boxes to have a decent chance of getting another super rare.... which explains why they're commanding such a huge price on ebay.
On the lookout for MISB Headmaster Highbrow, Takara or Hasbro. I'm sure I could make you a sweet deal!