I was able to find the setup for jasper server from https://sourceforge.net/projects/jasperserver/files/latest/download.
I want to know that is jasper server free or do we have to bear the some cost of it for usage.
The community edition is free to use with licensing restrictions (check out the license), there are paid versions as well and a cloud based Amazon AWS version too. Contact Jaspersoft for specifics if you have further questions, they're great about providing information and support.
The community edition is absolutely free, fine for production systems, and is perfectly legal to use that way.
The community edition is under http://www.gnu.org/licenses/agpl-3.0.html , for specific restrictions etc. contact Jaspersoft. I've used the community edition in multiple production systems without issue. The premium editions come with more features etc., and I think is also required if you're supporting multiple organizations/tennats with the same install. For supporting one organization you're fine. If that is an issue contact jaspersoft for details.