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It all depends on what type of marriage and scale of the event that youare planning. I think it would run in to a few lakhs or even more than 10 Lakhs depending on the venue, food, decorations, facilities, duration, activities in the fuction, etc.
But I would suggest you to take a contract with a hotel's hall so that you can finish marriage in a day and provide food & beverages and cut costs, time and energy.
Most restuarants and 3-star hotels provide these facilities. This way you can have a control on budget and also have proper bills and evidence.
Also beware of gifts or monetary considerations that are involved in a marriage. There is an alarming number of false dowry cases and also genuine dowry cases being filed. So be cautious. Visit www.498a.org for more details.