Let’s elaborate on your rough calculations:
According to official US defence sources the cost of Greece’s 123 plane upgrade kit will cost them 2.4 billion dollars. This includes 125 Aesa radars and 123 kits of avionics etc.
www.dsca.mil
That means Greeks are paying just under 20 million dollars per kit. I can’t see us paying a great deal more than that. So for the 79 kits, it totals 1.55 billion dollars.
Regarding the F16 V70 planes themselves; there are various quotes made by LM:
Slovakia they have been offered 14 planes for 800million. That is 57 million a piece.
For Colombia they have offered 108 million dollars a piece for 24 planes and 133 million dollars a piece for 12 planes. However these include variety of different munitions.
Bulgaria is contemplating to buy 8 F16 planes for 1.3 billion. That means 162 million a piece.
Below site quotes f16v70 price to be 63million a piece
Explore the top 10 list featuring high-tech aircraft with the highest price tags in today's aviation market. Discover the most expensive fighter jets of 2024.
www.aerotime.aero
As Turkey will want to produce these aircrafts and their engines in house at Tusas and TEI, I can’t see us paying more than Slovakian planes.
So that makes 2.4 billion for the 40 planes.
Regarding 600 AAMs:
If we are thinking of buying the long range AIM 120 D version (Since we have Gokdogan in production it is only apt to think that we will go for the Aim 120D) : UK ordered 200 of them for 650 million dollars. Making it 3.25 million a piece. So for 600 missiles it would total 1.95 billion dollars.
Regarding the 800 Precision Guided Munition :
It s difficult to guess what we would be buying from US, since we have so many different versions of this type of munition in our inventory. The only munition that makes sense is something like an AGM-88G HARM as Akbaba is still in development stage (Since Greeks have recently ordered the E version) at a price of nearly 1 million a piece making 0.8 billion.
So in total the logical payable cost of this order should be no more than 6 billion dollars. 20 billion dollars is outrageously high and in explicable.