The Russian origin Sukhoi-30MKI is Indian Air force's Primary multirole fighter. Many deals were signed with varying costs and other factors. Here is a comprehensive research on how much it costs.
Deal 1(30th Nov 1996): 40 Su-30 jets(8 Su-30K(or MK1), 8 Su-30MK2, 12 Su-30MK3 & 12 Su-30MKI) costs Rs 5,122 crore($1,462 million).
Deal 2(Sep 1998): 10 Su-30K jets costs Rs 1,187 crore($277.01 million). Unit cost $27.7 million.
There was also an additional expenditure of Rs 1,188 crore for indigenous development and import of avionics system for the Su-30MKI. A new deal worth $270 million for replacing the Su-30K acquired in Deals 1 & 2 with new MKIs, was reported. But the status of this deal is unknown.
Deal 3(Oct-Dec 2000): 140 Su-30MKI jets to be manufactured by HAL at a total cost of $4,809 million(Rs 22,122.78 crore). $4,809 million includes: Cost for license, ToT(Transfer of Technology), assistance & for setting up the production line in HAL(Hindustan Aeronautics Limited), $350 million or less for components procured from Irkut which wasn't manufactured by HAL, 26 aircraft kits supplied by Irkut & assembled by HAL, and the actual production in HAL. So the average cost of the HAL manufactured fighter is $34.35 million.
But that's not the whole story. Rs 22,122.78 crore for 140 aircraft in 2000 had to be revised to Rs 39,224.09 crore in July 2005. The cost is now estimated to be more than Rs 45,000 crore. For exchange rate of 46 Rupees for every U.S dollar that translates to $4809 million, $8527 million & $9783 million respectively. So price of each HAL manufactured Su-30MKI has increased from $34.35 million in 2000, to $61 million in 2005, to finally $70 million currently, according to CAG's(Comptroller and Auditor General of India) estimation.
Deal 4(March 2007): In addition to licensed manufacture of 140 SU-30 aircraft by M/s Hindustan Aeronautics Limited (HAL), a contact for procurement of additional 40 SU-30 MKI was signed with M/s HAL in 2007. M/s HAL would be procuring the technical kits from Russia and assembling the aircraft. The cost of the deal was Rs 9,036.84 crore. The aircraft were to be delivered in a phased manner between 2008-11. At an exchange rate of 44.2 in March 2007, that translates to a cost of $51.1 million for a single MKI.
Deal 5: Initially it was reported that 50 Su-30MKI jets are to be acquired from HAL. Unit flyaway cost around $45 million. So the total cost will be around $2250 million. However the deal was revised to only 42 jets, which includes several upgrades. The cost of the deal is reported to be over Rs 20,000 crores or over $4 billion. That translates to an unit cost of more than $95 million!! It appears CAG's estimation of cost overruns in Deal 3 is finally allocated in this deal, or is the price of a single Su-30MKI really over $95 million? In the end it turned out that the price escalation had a simple explanation and had nothing to with "Russian Treachery" or MOD corruption. It was as usual, dumb reporting from unprofessional Indian media outlets. The deal stipulates that the 42 Su-30MKI will be delivered to India, by Irkutsk, in semi-knocked down condition, at a cost of only 38 million dollars each.
Reference 7 - Each MKI to cost 38 Million dollars each