Have never visted Narita, but have been to Singapore many times. The costs of rooms in Singpoare are EXTREMELY expensive. I believe the cheapest that I was able to obtain while staying at "good" hotels was around 350 Sing dollars (which is still around 300 per night). Do a little homework and you may find better deals, I can recommend the Fairmont, The Hilton on Orhard and The SwissHotel at Merchant Court. Beatiful place, hope your enjoy your trip - Do not chew gum or litter.