The cheapest, at least from your point of view, is to simply arrange a press photocall and invite the press along. Assuming you aren't unlucky and there aren't a number of other events competing for media attention at the same time a number of photographers will turn up to take pictures. If they are working for a specific newspaper, either on the full-time payroll or, more likely these days, covering a shift on a freelance basis, then they are getting paid for being there and taking the images and if the story is felt to be important enough on the day it will get into the paper or onto the website. While you will be able to link to the media site you won't automatically be able to use the images on your own site without some payment. Other freelance photographers who turn up aren't getting paid to be there and need to make their money in a different way. This is done by circulating their images around the media, either directly or via a picture agency, and hoping that papers or websites that didn't have their own photographer at the event will decide they still need a picture and pay to use it. Without a sale the photographer was working for nothing, although there is still the possibility that the image may be bought in the future to illustrate another story. And that way a single image, perhaps a headshot of a politician or business leader could generate repeated income, if the photographer is lucky!