Dear browmmola
We remember when we could get to Manado for around $800.00 and Bali for even less but now things are the way they are. Even if you find a cheaper price you probably will not beat it by a whole lot as July is the busy season. You may still want to try going thru one of the larger travel agencys as they do buy blocks of tickets at a cheaper price to resell.
As far as looking for another place to go we guess it is what you think that you will get for your money, once you get to Manado you can find some very good deals which may offset the price of the airfare and the diving if you have not already been to Indonesia is worth the price and the travel.