Turns out it costs like 50 bucks to purchase.




http://shop.lego.com/Product/factory/pr ... a798bd6192
The Trailer includes a little Roller and that robot arm doctor thingy.
I don't actually own an RTS Prime, so if anyone has him and knows of a better way to make him connect to the trailer, please comment.
You can fit one Mini-con or similarly sized figure in there.
To get Roller to fit you'd need to remove the gun.
Please comment with feedback or suggestions.