Well i just played a quick game to see how OohSooBig's numbers worked out.
Started searching for a game at 15.42 found game at 15.54. (after one game failed to start) Hanging by a thread, lag was pretty bad on my end. actually got disconnected (managed to reconnect tho). We lost the game at 14.11. Got a score of about 3 (rubbish i know).
Gold reward was 3578, 2 of us opted for gold so received  1789 for 29 minutes playing/searching for a game.
Your not going to win all your games.  So yes his numbers were not to off.  Far to much of a grind, sadly.

Ive got to agree, 120000 or £19.99 to unlock her is way to steep.  If  Dr. Kuzmann is the same price, thats the same cost as the founders pack to unlock 2 characters, crazy, just crazy   
And to grind to earn 120000 coins, your looking at 40 or 50 thirty minute games at least.  thats a hell of a lot.  The characters should definitely be free if you've bought the single campaign.  The 10 day wait is punishment enough.