How do I buy devexpress dll for my c# windows application

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C#

Windows

in my project:DevExpress tool's dll,which are being used for successful project compilation are as-

DevExpress.Data.v9.2.dll
DevExpress.Utils.v9.2.dll
DevExpress.XtraBars.v9.2.dll
DevExpress.XtraEditors.v9.2.dll
DevExpress.XtraNavBar.v9.2.Design.dll
DevExpress.XtraNavBar.v9.2.dll
DevExpress.XtraPrinting.v9.2.dll
DevExpress.XtraReports.v9.2.dll
DevExpress.XtraReports.v9.2..design.dll
DevExpress.XtraTreeList.v9.2.dll

in Project we need to buy the license version of above DLLs.I need guidance to proceed.
My questions here are that: Do we need to buy whole package of reporting ?will it be enough or some more packaged need to procure ? Is only required module (related to above mentioned dlls)purchase is possible?Apart from DevExpress.com I found a INDIAN AUTHORISED DISTRIBUTOR WEBSITE TOO as componentsource.com.How can i check the authentication for this site as there is price difference in these two websites costs for modules.Later one is providing in cheaper price.