Cheapest way to Komplete Ultimate so far is to buy the full version KONTAKT 5 and then crossgrade.
More "bang for buck" would be to get a Maschine MK 2 then crossgrade to Komplete Ultimate (as you end up buying Kontakt twice the other way), but then you spend more money.
From what I can see Native Instruments have got these buying options knotted up quite well.