Hero Forge and Spell Forge are two very useful character creation tools, the DM will determine which books will be allowed, the site update periodically however the group will use the same version that the DM has. However it only runs on Microsoft Excel and to run it go to Tools > Macro > Security > Setting: Low. You will then need to close all Excel files and open it again for the change to take place

The SRD has all the information for a core rule game in an easy to access format, however you will still need the books as some rules and monsters are Dungeons and Dragons trademarked.

If you do not have Microsoft Office than this is a useful character creator, you will need to have Java installed on your computer in order to run this though.