The reason why you can get all this stuff for free is simple: companies give it away as promotional material. Most of the time the free stuff, such as hats and t-shirts, have a logo on them of the company giving them away. Other times you'll see samples and trials of items that are new on the market and that companies want you to see and try. It's really not as fishy as you think it might be and you'll quickly see that a lot of the freebies I post on here are from big name companies that are giving away some decent stuff. Just think about it, the best way to get feedback on a new product or build buzz for it is to give away 10,000 trial samples.