Valuing the share price of a private company is quite a bit trickier than pricing public stocks. The information is not always publicly available, and no regularly published reports are available for easy access. However, the process is not impossible, and with a little research, the share price of private stock can be accurately verified.
Sell the company. If the company in question is your own, and you'd like to know the per share price, put it on the market for sale. Much of a company's value is rather subjective and based on perception or market conditions. Thus, even if you carefully evaluate the company's worth, the price you get upon selling it might be considerably different. Dividing this price by the number of issued shares will give you your per share price.
Read everything you can about the company. Call the owners and ask them how many issued shares it has. Also, compare the company to other privately owned companies that are similar and on sale or which have been recently bought. You can also compare the company to similarly sized public companies, but if you do this keep in mind that public companies are often valued much higher on a per share basis than similarly sized private counterparts.
Add up the value of all the company's assets. Measure the value of its material assets, i's accounts, its goodwill, and, as well as possible, intangible assets like brand names and upcoming products. Include in these measurements all the outstanding liabilities and subtract them from your asset valuation. Divide this value by the number of issued shares.