Here's some interesting new details:
www.cnbcindonesia.com
9 billion USD for 42 J-10s, vs 8.1 billion USD for 42 Rafales.
Since the price for a J-10 is much cheaper than a Rafale, the bigger cost for the J-10 acquisition is quite something.

Purbaya Setujui Pembelian Fighter Jet Chengdu J-10, Nilainya US$ 9 M
Menteri Keuangan Purbaya Yudhi Sadewa mengonfirmasi anggaran US$ 9 miliar untuk pembelian jet tempur Chengdu J-10 dari China. Impor dijadwalkan segera.

9 billion USD for 42 J-10s, vs 8.1 billion USD for 42 Rafales.
Since the price for a J-10 is much cheaper than a Rafale, the bigger cost for the J-10 acquisition is quite something.