A Fan Page is always related to a Profile, you can't separate them. So, you need someone who is selling you a FB account with an existing Fan Page which is rare to find.
I suggest, buy an aged FB Profile with followers, warming it up, add some fake followers post some valuable content and convert your Profile to a Page.
Now you have your Fan Page with followers, start an engagement campaign optimize for Page Likes and at the same time, get rit off all your fake followers. (not all by one)
Also important, a seller who provide you the related e-mail for a verification mail.
And don't forget to use good proxies