I had one extra OK Bull left from a recent eBay purchase. However it had a missing right hand weapon and no head. So I debated about finishing it off as a bull but I have plenty of those at present. However I am in need of a Tyrant and since those models are quite expensive and I already had half an ogre I decided to convert him.
A new Tyrant from GW is $40. The average price of a OK Tyrant on eBay is going for $25 to $40 USD with shipping costs added to the price. I did some bitz shopping and spent a total with shipping of $13.60. So that is about a 40% savings off of an eBay Tyrant and a huge savings from retail GW one.
So here is with his right hand cut off and his gut shield removed while he awaits his new parts.