The public offering price is what you have to pay in certain situations to invest in.
The term is most often used in two contexts.
A fund has a NAV of $10 per share and charges an 8.5% sales load. In this case, the public offering price will be 8.5% higher than $10, or $10.85 per share. If you invest $1,000 in the fund, you'll receive just under 92.2 shares of the fund. However, the value of those shares will be just $922, or $10 per share. Put another way, the NAV would have to rise 8.5% just for you to break even on your investment.