Is it risky to give out credit card and other personal info for Internet ads offering something for free?

[jazzyguy17]

I get lots of marketing emails offering "free" products but then they ask for personal information such as credit card info so that they can deduct a minimal shipping and handling fee. Is this some kind of scam? Some of them tell you you have to sign up for one or two offers from a list of about 2 dozen in order to get the "free" item. Isn't this unfair marketing or illegal? I get these emails all the time and after I start filling in the required information I realize I'm getting taken because they want your personal information and try to make it seem innocent by telling you they have to collect a S & H fee.