Qatar's finance minister, Ali Shareef Al Emadi, recently told journalists that the country is spending $500 million (£400m) a week on major infrastructure in order to have things up and running for the 2022 World Cup. By the time it's all said and done, it will cost an estimated $200 billion to put on the tournament. Here's more from The Guardian:
Emadi said this figure covered not only stadiums but huge and costly projects such as roads, a new airport and hospitals.
"90% of the 2022 contracts have already been awarded," added Emadi.
"That doesn't mean the stadiums only, we are talking about highways, rail, ports, airports, those are really underway, even hospitals and everything."
He added: "We are really giving ourselves a good chance of delivering things on time and we don't want to get in a place that we start painting while people are coming to the country."
Emadi doesn't think this will be the most expensive World Cup ever, but that's because of a technicality: the money is also going into infrastructure – the aforementioned roads and hospitals – and isn't specifically tied to football. Which is... okay, let's just go along with that. Governments generally rope themselves into enormous international sporting tournaments so they can build roads for the public. Happens all the time.
For reference, Brazil spent $11 billion to host the 2014 World Cup and Russia is spending $10.7 billion on 2018.
Naturally, someone has to do all of this work, and that has fallen to a largely migrant worker class; reports of systemic abuse have been rampant. Last March, Amnesty International interviewed 132 migrant construction workers rebuilding Khalifa stadium and another 99 landscapers – mostly from India, Bangladesh, and Nepal – and all 231 reported some kind of abuse, including threats for complaining about working conditions, lack of timely pay, horrible living and working conditions, and employers confiscating immigration documentation so the workers couldn't leave.