It took me around 4 months to figure it out where to find free stuff. There is a huge collection of item available online. The important thing is to how to tap them. There is no free lunch. This is a proverb that we mostly have listened over the years, and yes it is also true in this case. You have to put some effort to get these things. The first thing which should be done is to do a proper market research. Several hours have to be dedicated to this thing. Other techniques which could be employed are described below.
Become a good reviewer. A good reviewer is a person whose reviews are liked by people. The simplest way is start writing review. After some time you will get to know what kind of reviews people love. I started my reviews on amazon, and after some time I became a Vine member. As a member I received several promotional item for reviews. The other thing which could be done is to sign up with promotional websites for free item. There are other places where you can actually get money and several other things by just giving some services. This mostly involves filling a questionnaire for referringproduct to your friend or family.
There are several websites where I have found free stuff. One of the best site I got to know about is friistuff.com. There are many electronic products given out on promotional basis.