How to create a page without custom master page. I want v4 master page for that page.
How about a application page? Creating Application Pages for SharePoint
"An application page is an ASP.NET Web page that is designed for use in a SharePoint Web site. Application pages are a specialized type of ASP.NET page. The primary difference between an application page and a standard ASP.NET page is that an application page contains content that is merged with a SharePoint master page. A master page enables application pages to share the same appearance and behavior as other pages on a site.
You can explicitly change which master page is used by the application page by setting the MasterPageFile attribute of the application Page element. (For example: MasterPageFile="~/_layouts/applicationv4.master"). In fact, you must set this attribute if dynamic master pages are not enabled on the SharePoint server."
You can change the MasterPage on a non-publishing site via 'Change the Look' in site settings.
Simply navigate to Site settings then click on “Change the look”.
On the Themes page click on the theme that you are using.
Next on the left pane you can select the master page for this theme.
Next click on “Try it Out” and then “Yes, keep it”
and you’re done