AMD would like to regain market share while still making a decent profit on each unit sold. A Pitcairn-sized die on 14LPP is ideally positioned to let them do that.
Back in 2012, AMD released the cut-down Pitcairn (7850) for $249, and it was widely considered one of the best perf/$ offerings at the time. The full Pitcairn SKU (7870) was $349. I expect that we'll see similar pricing for Polaris 10 cards. I know a lot of people talk up how expensive FinFET chips allegedly are, and while I don't doubt the wafers are more expensive than 28nm wafers
now, we should instead be asking how the cost compares to that of 28nm wafers back in
2012 when that node was just starting up. I found some contemporary
articles talking about how expensive 28nm wafers were, so the current teething pains are not unique to FinFET. If anything, the current FinFET nodes are more mature than 28nm was in early 2012, since the early adopter premiums were paid by Apple and Samsung. I believe that the bill of materials for a Polaris 10 card now will be no more than it was for a Pitcairn card back in 2012. Memory bus width is the same, TDP/power consumption should be the same or lower, and I think GDDR5 costs have gone down far enough to offset the increased capacity on newer cards.
Think about what AMD is currently selling at these price points. R9 390 is in the $300-$330 range, and that's a Hawaii chip (438mm^2) with an ultra-wide 512-bit memory bus (more PCB layers, more GDDR5X chips) and a massive TDP (beefier power stage and larger cooler required). Polaris 10 has got to be more profitable than that, while still providing a better deal to customers.
I expect the cut Polaris 10 ("R9 480") to provide performance similar to R9 390/390X for $249, and the full Polaris 10 with higher clocks at $349 ("R9 480X") to provide performance roughly on par with Fury X overall: maybe ~10% higher at 1080p, and ~10% less at 4K. Both cards will provide considerably better perf/$ than anything currently on the market.