It's free and open to use non-commercially
If you want to use RGraph on a non-commercial website then just go ahead. RGraph uses the Creative Commons BY-NC license which means that if you wish to use RGraph on a non-commercial website then go on - it's free! All of the source is included in the archive and if you want to change it to meet your needs then go ahead. - there's no restrictions on doing so.
If you want to use RGraph commercially or just don't wish to link to the RGraph website then a Standard license for RGraph is not 1000's - it's just £99 (the cheapest of the commercial chart libraries?). So if you find the idea of paying excessive amounts of your hard earned money a bitter pill to swallow then RGraph is a good bet.
Use the canvas tag to create super-fast HTML5 charts and graphs
Lots of features and documentation
There are lots of plus points to using RGraph to make your charts with, which you can see from the RGraph documentation and these points:
If you want to use RGraph on a non-commercial website then go right ahead - no license purchase is necessary. It uses the Creative Commons BY-NC license. You can also make changes to the RGraph libraries as and when you need to.
Download it and try it out
The best way to find out what RGraph is like is to download it and try it out! Simply head on over to the download page to get hold of it.