If you are a beginner and want some free tools for making or editing 3D models then I have some suggestions for you. These tools are by no means the only tools you can use but they are free and do the job:
Anim8tor is a free program (http://www.anim8or.com) which takes up less than 2MB! It is a Windows program but does not require any install so it can easily be put on USB stick and run from any computer. It takes a bit getting use to (there is a manual available) but it can basically do almost anything (right down to moving each point in the object mesh). For WebGL you can use the export option to export the model and then write simple code to import it into a WebGL program or use my WebGL JOA Framework (http://webtable.byethost15.com/WebGL) to do so. When not using the tool for WebGL it can be used to define bones in objects and then bend the objects. Sequences can be recorded to make repeated animation easier and then the entire scene can be arranged and recorded (including moving cameras, etc). An excellent tool regardless if you use it for WebGL or not.
I really admire this program. It may not be the best GUI program but it has tonnes of features and all of it is packed into less than 2MB of disk space!
MeshLab is a free program for manipulating 3D objects. I have not played with it too much so far but it has many different filters to do all kinds of operations on your 3D objects including a polygon reduction filter. This can be used to try to reduce the complexity of a 3D object with minimal structural loss. Typically objects rendered for WebGL do not need as much detail as some model provide. In such a case the polygon reduction filter can be applied to reduce the number of polygons and still keep the basic shape. Meshlab is also a great format conversion tool because it can import and export many different formats (of which some are compatible with my JOA Framework so they can be loaded directly by the framework without modification).
Note: I am not affiliated with either of these programs and I gain nothing by "promoting" them here. I am just indicating my experience with these programs and suggesting them to others who might be looking for similar programs.