I can only speculate, but I think this estimate will be very accurate, although it's my math, not an industry expert.
Judiging by the differences in price AMD has announced, between the different 8 core chips that are going to ship soon, I'd guess $350. Since the announced 8130P runs $320, $30 more than it's lesser brethren.
Now, there's two things to consider when talking about the next series of chips. AMD says these first Zambezi chips will only have a 6 month shelf life, this is 100% verified, directly from AMD. So..
What they're saying is, the next version/revision of these chips are going to be better, I'm assuming higher clock speeds, and probably new products aimed a bit lower into the budget area. Anyway, we'll certainly be seeing these chips so early because of Ivy Bridge, the timing is nearly exact, so this is extremely likely why the short shelf life. They believe these chips will compete with SB, and once IB is here, they're going to wash them out entirely for the new chips, which makes perfect sense, since this 2nd release is a full update, so there's no need to continue selling these chips due in Aug/Sept, first because the newer chips will be so much better, second because these first chips may not compete with IB (certainly not overclocking, and these are FX so, OC is a big deal I'm sure) and third, it's not possible to simply lower the price on these early chips to sell at a value, because it would kill the sales of the newly revised, early 2012 chips. It would still be costly to produce the chips so early into their lifecycle, so keeping them around and slashing prices seems out of the question.
I'm greatly hoping for a 140w TDP chip, it would certainly have a base of at least 4.0-4.2Ghz, and turbo to 4.5-4.7Ghz. If we don't get a 140w TDP, I have a feeling with the second revision, well third total actually, they may be able to push these numbers with 125w TDP.
They obviously expect some pretty big gains, well they've said so, with these 2nd, early 2012 chips. We just don't know if it's their assumption they'll get better quality chips, or use higher TDP, or perhaps both, I'm hoping both. At the very least, they intend to have better performance as a result of maturity by then.
Anyway, I'm 100% going to do what I mentioned, and so I'll have the 8130P at half price. While I plan to OC, it won't be anything extreme, and it will have the remainder of 2 1/2 years warrenty on it. If you have something else by then, that's fine I'm sure someone else here would love to grab the chip at half price. The 8130P may not even be available anymore, by then.
(All of this is assuming Zambezi actually ships by September, though it should)