https://donotcall.gov/
WHAT YOU SHOULD KNOW ABOUT THE NATIONAL DO NOT CALL REGISTRY
The National Do Not Call Registry gives you a choice about whether to receive telemarketing calls at home. Most telemarketers should not call your number once it has been on the registry for 31 days.

https://www.optoutprescreen.com
The FCRA also provides you the right to “Opt-Out”, which prevents Consumer Credit Reporting Companies from providing your credit file information for Firm Offers.
If you choose to Opt-Out, you will no longer be included in firm offer lists provided by these four consumer credit reporting companies.

http://www.fcc.gov/cgb/consumerfacts/unwantedfaxes.html
Fax Advertising: What You Need to Know
The Telephone Consumer Protection Act (TCPA) and Federal Communications Commission (FCC) rules generally prohibit most unsolicited facsimile (fax) advertisements. In addition, the Junk Fax Prevention Act, passed by Congress in 2005, directs the FCC to amend its rules adopted pursuant to the TCPA regarding fax advertising. The FCC’s revised rules: (1) codify an established business relationship (EBR) exemption to the prohibition on sending unsolicited fax advertisements; (2) define EBR for unsolicited fax advertisements; (3) require the sender of fax advertisements to provide specified notice and contact information on the fax that allows recipients to “opt-out” of any future faxes from the sender; and (4) specify the circumstances under which a request to “opt-out” complies with the Act.

http://donotmail.org/
Unlike donotcall.gov, there is not a way to opt-out of junk mail. Places like donotmail.org are trying to change that.

Corporate junk mailers stuff American mailboxes with more than 1 billion pieces of mail each year. In fact, junk mail in the United States accounts for nearly 30% of all the mail delivered in the world.
But junk mail does more than simply invade our homes and waste our time. Junk mail also puts us at risk of identity theft, destroys forests, contributes to climate change, and creates more waste for landfills. What’s worse, taxpayers often have to bear the cost to dispose of this garbage while junk mailers often get huge (and sometimes subsidized) discounts to send us more junk.

We need some common sense solutions: let’s take back our mailboxes and change the way these junk mail companies do business.