Google Adsense

Has anyone tried Google Adsense? I recently paid $2.95 to Profitstudiolearning.com thinking of getting some information but it got me into this $69.99/monthly program automatically after 7 days trial. I cancelled the program right away because it needs website to start which I was not told before I paid. Anyway, then I found out Google Adsense is a free program. Anyone has website can sign up and start to list Google ad on their web sites. Appreciate any experiences sharing here. Thanks.