Hey Sweccha,
Here are only two budget properties i could find on neil :-
Hotel Kingfisher -
Beach No 2, Neil Kendra, Neil Island, Andaman and Nicobar Islands 744104
03192 234 788
Hotel Amulya -
: 91-9933215566
It's better you taje a chance, get down from ferry on Neil and then search a stay option ... online seems to be too costly ...
Happy Travelling!!!