www.constantcontent.com is a website I used often when I first started working as a freelance writer. It is different from other sites because you post the article, review, video or pictures. Then you get to pick how much you would like to sell it for.
They have different ways you can sell it: Usage which is where someone pays to use the article in one place on their website. You can continue selling the content on the website and others may buy it. The usage price is usually relatively low because the purchaser knows that it is not exclusive content. The next way an article can be sold is with unique rights. Most purchasers prefer this option. The information is completely purchased and the article is removed from constant content so that no one else can purchase it and it is exclusive to the purchaser. Through this option I have found some great employers. A few of whom still contact me on a regular basis to create content for them. The price for unique articles is usually much higher because it is a one time sale. Full Rights is the last purchase option. When someone buys your information this way, they are allowed to change wording, remove your byline and use the information on multiple sites. As you can imagine this is the most expensive option.
Constant Content also provides information about what purchasers have requested. This often helped me overcome writers block because I could scroll through and find something that someone was looking for and write about it. This also ups your chances of selling information because you know there is someone who is looking specifically for it. But they will accept writing on just about any subject. I have posted articles on constant content from jobs that never pulled through (this doesn't happen often, but a few times I had already created articles for a job and then the employer bailed) When this happens don't take it too hard, it is bound to happen in freelancing. But you have done the work so you can still make money by posting it on constant content.