I just did one yesterday, in fact. $110 for 2 hrs of tasting and talking about a food product. I've done many over the years. They are always fun and well worth the time. You have to be outgoing/talkative enough to give your thoughts/feelings/opinions in a group of total strangers. You are usually being observed by people behind a one way mirror, who are taking notes. Yesterday it was several people in the room with us, each had a laptop, taking notes. I have a feeling that if you just "show up" and don't actively participate in the discussion, you won't be called back.
They send me emails with links to screening questions when a focus group is going to be held near me. Make sure you answer these truthfully bc often the same questions are given to you in the form of a paper when you arrive at the site for the group. If your answers are drastically different from what you answered in your screening, they will call you on it. I've seen it happen. Be on time or better yet, early!!! They start the group sessions on time. If you are late, they will send you home w/o the pay. They usually invite more to the group than they actually need. Like if they need 10, they will invite 12 bc of no-shows or late comers. So if ALL show up, the ones not needed get to go home WITH the promised pay!! That happened to me once and once to my daughter!