possibly below the cost that PLAN paid, china clearly gave Pakistan a huge discount, probably helped that these are mass produced so prices are cheaper than before and with some PRC government assistance push it well under 300 million. there is no exact number since this info is from rumors from some credible leakers.
for comparison, the offer to thailand in 2013 was a bit over 1 billion for 3.
That said, news is that the 054B is being built right now. should have better longer ranged SAMs and munitions options while still being much cheaper than a 052D.
052D is expensive too, like 540 million,but i suppose 2 or 3 could be affordable over the long run, and would be more useful for Pakistan than a single 055. but then again you could get like 5 054B for the same price.