The two budget airlines operating from chennai/ Bangalore to Singapore are tiger airways and air asia.
Air asia is cheaper but has a stop over at kuala lumpur. Tiger airways fly directly and i have taken it for my trips to Singapore from Chennai. the timing is good.

the price range is around USD 165 for a round trip from chennai to singapore.

for accomodation www.booking.com is the best booking site for decent hotel booking site.

www.tigerairways.com
www.airasia.com