Basically there are a lot of manufacturers who work with materials such as metal and wood, and they will always have scrap materials that they need to dispose of. For these companies it is not profitable to find someone that they can sell these materials at a discount so they basically just give it away to anyone who wants it. The good news is that for you or me, this is profitable. Since you are getting these materials for free then you can sell them for very cheap to whoever wants it.
When I first saw this, I was thinking that a college student like me has no way of storing wood chips and pieces of metal, but then I came up with a way.
Find the materials you want to sell, then find a buyer, and then just tell the supplier to send it to the buyer. Simple.
Chances are since they are giving away the materials for free that the manufacturer will not want to be in charge of shipping it to you. In this case you will need to find a local manufacturer and have a car. It is a little less convenient but still a profitable operation.
Now the important thing is to find a site that provides a list of updated materials for free within your local area.
I live in England and I have found eastex.org.uk to be the most convenient site. It has a simple interface and is fairly local for me.
This method of making money is a little less 'virtual' than what I would like the posts on this site to be, but I think it has some potential.
EARNING POTENTIAL:
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