Melbourne 2006 Commonwealth games cost a whopping $1.5billion AUD (about £600 million GBP; about 3% of the current estimate for the 2012 Olympics).
Now the Delhi 2010 games did go vastly overbudget, possibly as high as 60,000 crore INR (about £7 billion; less than half the current estimate for the Olympics). But they also built a 4 lane highway, new metro tunnels, and expanded the airport in that price. About one-quarter of that gross estimate was budget spent on the sporting events and directly related infrastructure.
There are 302 events at the 2012 Olympics versus 272 at the 2010 Commonwealth games.
