I've been obtaining free stuff for over 10 years. I have learned a few key things along the way.
1. Create a separate e-mail address. Grab a free e-mail address from either Yahoo or Gmail to use exclusively for signing up for freebies. If you don't, you'll quickly see that your main e-mail account is swamped with e-mails that you really have no interest in reading. Then you'll have to spend all your time clicking the unsubscribe links in each e-mail.
2. Join some freebie forums. It takes too much time to try and hunt down all the new freebies that pop up. Joining a few reputable freebie forums is the best way to keep your eye out for great deals. Checking them once per day will only take about five or 10 minutes. This is where I find most of the freebies I sign up for.
3. Some freebies aren't worth it. Don't sign up for every freebie you come across. Some sites require you to give away a ton of your private information, sign up for other deals, or take surveys that really end up requiring you to purchase something. These are not worth it. To me, time is money. If it is going to take me more than one to two minutes to fill out a form to get the freebie, then I won't do it.
4. Check in with Walmart and Target. Both Walmart and Target have their own free sample section. I check these once per week in addition to the freebie forums because they always have name brand products that I can try totally for free.
5. Be patient. You are likely to forget about the free samples you requested before they actually show up at your house. Typically, it takes between six and eight weeks to get your free sample. If you are an organized individual, just keep a notebook handy with a list of all the freebies you requested and the dates that you requested them. You can check them off as they arrive.