Los Angeles, 1984
LA had it relatively easy as they already had the main stadium there after hosting the Olympics in 1932. They saved cash by improving existing venues - only the velodrome and the aquatics centre were brand new.
The games were turned into big business, without the need for reaping the tax payers' cash. As would be repeated again by the Americans, sponsorship was key. In the end they turned a profit of $200m. LA was already established before the Olympics so the focus was more on the sports themselves without wasting money or political influence.