You should contact your local well know trip adviser or tour planner as every person is from different places and there will be different packages for solo trips.
It can be easily done within 40k including flights, stay and food and commutation within the city.
Books your flights well in advance and opt for Hostels or Couch Surfers for your stay.It won't exceed 45k anyday if planned properly for a stay for a week.
Hey, Depends on what kind of Traveler you are. if you are budget traveler, you can easily do Bali Trip for 6 days in 30-40 k, why I kept 10 k Gap. it's because someday you might indulge in luxury dining or you might get expensive flight.
accomodations should be either through couch surfing or basic hostels, public transport and local food.
Though it totally depends on the kind of expenditure you are willing to make. Book reasonable homestays or lavish villas. But on an average close to 50K atleast