Before participating in these or any other free offers, I suggest you set up an email address especially for free sample and coupon offers.

You can set up a free gmail account for this purpose. You can also set up a free phone number (accepts voicemails only) to use for these offers.

Don't ever give out your home or cell phone number unless you WANT solicitors to call you. Many of these companies have a strict privacy policy but many give away free stuff for the sole purpose of collecting information for marketing purposes.

For more information on this top, there's a great article here.