The evil of producing a medieval fantasy series such as this one is that it is expensive. To make it look good is very expensive. So what kind of budget is Game of Thrones likely to get?
If we look again at Rome as a guide, we see that the budget was massive, $100 million for 12 1-hour episodes. That works out to a little over $8 million per episode. Is HBO willing to invest that much money into Thrones, especially after they canceled Rome mostly due to the large production costs? Probably not. The good news is that part of the reason for Rome’s massive budget was due to them filming in Rome itself, at Cinecittà, one of the most expensive studios in the world. Game of Thrones will be filming in a presumably much cheaper studio in the UK. So they won’t likely need 8 mill per episode.
Let’s look at another historical drama series, Showtime’s The Tudors. The Tudors is shot in Ireland, which is quite possibly where Thrones will film. It has costumes and sets similar to what Thrones would need. According to this article in the Seattle Times, the budget was around $3.5 million per episode. This is a much more reasonable amount and something that HBO is probably shooting for.
Now The Tudors doesn’t have need of many CGI effects or battle scenes. There were no direwolves or dragons in 16th-century England. As such, I believe that Game of Thrones may need a little more per episode than even The Tudors. To get the kind of professional production quality that HBO is known for, I am guessing they will need to budget around $5-6 million per episode. With the BBC already on board monetarily, I suspect that this is entirely possible.