Sometimes people just want it gone, and other times there are strings attached, but still free.
Some freebies require registration, be careful as to what information you give out.
Search the internet for freebies and you'll find tons of directories and portals to everything imaginable. I suggest you read the terms and conditions diligently, don't assume free means unlimited use, usually there are some terms.
Yards sales, garage sales, are great places to find good deals and some free deals at closing time. Watch for new stores/grand openings and vendor shows usually are giving samples away.
Volunteer for concerts, sporting events and fundraisers for charities and non-profits is a great way to get in a event for free. You will find plenty of free food, t-shirts and other products are given away by sponsors of the event.
Sometimes you may be unable to sell an item, so why not give it away rather than throw it away! Recylcing is great, helping someone in need is even better!