If you are looking for an online encyclopedia, they are not hard to find. A simple online search for online encyclopedias free will pop up tons of results. When looking for an online encyclopedia, it will probably benefit you to look fora free online encyclopedia. They are usually reliable, with facts about any topic you could want, and obviously it is better to not have to pay for the information if it is available for free.
There are also online encyclopedias that specialize in certain topics. For example, there are free online encyclopedias for animals, or for history. These will make it easier to find what articles you need, and give you less articles to look through if your articles are limited strictly to your subject of interest.
There are also online encyclopedias that are targeted towards younger users. They have broader and less in depth information about topics, making it more comprehensible for young children, but still allowing them to learn how to research using an encyclopedia. These are important skills that they will need later in their education, so providing them with a way to learn it without information that will overwhelm them is important.
However, there are times where a free online encyclopedia is not necessarily better than one you pay for. When looking at online encyclopedia free, be sure to note how reliable, or not reliable, they are as sources. Some free online encyclopedias are editable by the general public, and therefore can not be trusted to have one hundred percent accurate information at all times. While there are moderators who prevent people from posting nonsense to these free online encyclopedias, they can not be monitoring every page every second of every day. So be sure to check how the free online encyclopedia you use is monitored and who is allowed to edit the pages.