Read in Today (newspaper in Singapore),
www.todayonline.com, 28 January.
It seems that Indonesia has discontinued the 7 day visa on arrival; the only visa on demand available now is one for 30 days. The 7 day visa was cancelled to reduce graft.
The price of the 30 day visa is US$25 (I presume that's in US currency; I recall they don't take rupiah).