We used this service on our way home yesterday, we had 2 adults 2 children plus one unwell infant, they charged us 300,000 RUPIAH for all of us. This was quite reasonable as we had the use of comfortabloe sofas (there are also dining tables too), there is a smoking room, buffet of food such as spring rolls, samosas, noodles, soups, bread, sandwiches, pastries, cakes, fruit, soft drink and bar, toilets, shower, internet, praying room, airconditiong - that is all included in the cost.
Thanks to sparkyperth for recommending this to us.
it was very relaxing and comfortable and a nice end to our time in bali, as i dont think our kids would have sat as quietly in the airport departure section