My work provides the flu vaccine for free. This year was the first year I ever got one because of having a newborn in the house. I've never had the flu, but my wife had it last year and I know several others who have had it or have it now. You will know when you have it... It really beats you up. If you are in question, you probably had a cold or other less serious virus.
As to how effective the flu vaccine is. Each year it varies, this year they are saying those who got the vaccine are 62% less likely to get the flu. And for those who did get the vaccine and were still unlucky enough to get the flu, they tend to not get symptoms nearly as bad as those who did not.
I am friends with a couple of doctors. They are not in a position to make profit off of providing a flu vaccine. They both think it is a good idea. If you can afford it, I would get it.
