There used to be cheap (<1k) video transmitters long ago, but I don't know if they are still available somewhere.
Of the major cities in India, I'm least familiar with Delhi, so I can't advise you on where you might get them. I suggest you look in those markets where they sell electronic gadgets. Perhaps electronics parts shops in Lajpat Rai Market or in places where they sell imported gadgets.
As you have no experience in electronics, building one yourself is probably beyond your capability. The circuits are not too complex, but they involve high frequencies and wide bandwidths, and this requires skill in construction and electrical alignment. E.g., you might have a look at this:
http://petlibrary.tripod.com/rfmod.htm