It really depends on what you want. An avg hotel would cost you about Rs3000 per night but if you want a villa, it would start from 10k per night. A 8-10 hour can again will cost you around 3K/day, so you can plan accordingly. Food, tickets to the tourist attractions, etc. aren't very expensive. Also, watersports are not great either, you can totally skip it.
Both have their own charm, Cebu in the Philippines is a nice destination too, but I feel Bali gives you the best of both the worlds; the beaches and the mountains. Also, Bali is much more safe, so my vote goes to Bali :)
From Kolkata to Denpasar Flight fare will be around 18k Updown . And for 5 days in Bali you need around 25k . If you explore by yourself it's very cheap and budget friendly. Like take a International Driving licence if u want to rent a Bike . When I visited Bali I spent around 40k. If you want more details contact me