>How much would it be with in game gold?

It depends on what region you're in and how expensive WoW tokens are in that region at any given time (1 token = 1 month game time). I'm in the US region where they go for roughly 180k - 220k gold lately. Very expensive for a new player, but gold is easy to make on the auction house if you put in the time to learn.

If you're curious what determines the price of the tokens: people buy them with real money to sell them for gold on the AH. That way people with e.g. lots of money but little time IRL can fund their WoW adventures without having to farm or get involved with the auction house.