One thing which you should keep in mind is, that an amateur photographer will not be able to give you photo results like a professional one.
Professionals are called professionals for a reason.
Even if you wish to appoint an amateur one, make sure you guide him and give him samples and previews, of what you are expecting out of him.
As far as budget is concerned, a lot of budget-friendly photographers who are professionals, are available!
I don't think going for an amateur photographer for a function like wedding is a wise decision!