Free jqGrid is the fork of jqGrid. Its development is based on jqGrid 4.7 (before changing of license agreement). It can be used under MIT/GPLv2 license.
Starting with version 4.7.1 jqGrid is now Guriddo and it can be used under Creative Commons Attribution-NonCommercial 3.0 License (see the prices here).
Free jqGrid is the fork of jqGrid 4.7.0 and it can be used under MIT/GPLv2 licenses. It's available on GitHub here and from CDNs, from npm, bower, NuGet and Maven Central. The corresponding Wiki documentation can be found here and here.