Some have just been seeing some nice sale prices at their nearby Toyworld stores, and sure enough, the latest catalogue has the four main sizes of Transformers Siege on sale.
BUT, according to the back page of the catalogue, it only applies to 19 Toyworld stores... however, Toyworld stores (and the Mr Toys stores) sometimes price-match the Toyworld catalogue online if you show it to them... so give it a go if your store isn't on the list.

Micromaster - $15
Deluxe - $25
Voyager - $40
Leader - $70