It's almost impossible to say, and that's the fun part. Stock prices reflect the market's best guess as to the net future value of an asset, so on that basis, PPC's true worth is 0.00134000 BTC (up 5% last 24 hours!), or about $0.13 USD.
However, there are a couple of temporary factors that currently negatively influence the price.
First is the absence of true widespread liquidity; I would reasonably assume that 99%+ of the world has not heard of PPC. There will be a direct positive correlation between PPC awareness and its price, as demand begins to exceed supply.
Second is that there is really a very limited set of PPC for trade on exchanges. The coin supply is currently just under 19.5M PPC, but that number is deceiving. I would speculate that at least 10M of it is held by long-term investors who have zero intention of selling PPC anywhere near current price levels. I invested the money for fun, and won't be selling PPC for many years as a result, and I think many people hold similar views to me.
What does this mean? Any time PPC gets a short-term hit on popularity (a media article, a news report, a new vendor accepting PPC, a security issue with a competing cryptocurrency, etc.), price will spike in a very volatile way, because of the very limited supply. Right now prices have been stable the past couple weeks because demand is also low, but this can change in a hurry. We saw this in early April when PPC jumped to over 0.003/BTC.
For those two reasons, I expect the value of PPC to greatly increase over the next 10 years, as more widespread awareness increases the amount of consumers who wish to own PPC. People like Max Keiser target $100K per BTC in the future, which I think is overly ambitious, but I would not be surprised to see PPC at $500 five years from now.
To answer your question: I expect PPC to be worth about $2-5 a year from now (assuming proper marketing and no security issues), and worth either hundreds/thousands or zero 5+ years from now, depending on whether the market decides that PoS is the superior technology. It's a random walk down e-street.