We want to use discourse as a community portal in our commercial application.
Investigated - Its open source with GNU GPL licence.
Do we need commercial license for self-hosted discourse, if we need to include that in our commercial application.?
If yes, can anyone please provide the details regarding the license + support cost.?
You do not need to pay to use the software. You do need to pay for support (unless you can get it here). See https://github.com/discourse/discourse/blob/master/docs/INSTALL.md and the FAQ section of https://www.literatecomputing.com/product/discourse-install/. If you need support for a self hosted installation there are people like me who can help. (post in #marketplace or find my contact info in my profile).