Yes, hosting the Olympic Games helps the economy of its host by increasing tourism. Once a nation has hosted the Olympic Games, it is talked about more often in the rest of the world. This is a superb form of advertising, and makes that nation seem more appealing to visit.
Yes. The host country of the Olympic Games enjoys economic benefits for at least a temporary period of time prior to the start of the games, and shortly after the Games are finished. The host country typically receives federal funding to beautify the area in which the games are held, and they also are able to market licensed product from the respective games, even after the games are through.
A lot of money is put in for the preparations of the games , such as building of new venues for specific sports like basketball. Also, a lot of special effects and fireworks are used in the Opening Ceremony and maybe the Closing Ceremony which marks the start and end of the games respectively. This costs a lot of money and the host country may have less money after the Olympics have ended.