My husband worked for Philip Morris and received shares of stock in 92 and 97 at no cost to him. They were part of his benefits package. Sold stocks 24, is cost basis $0?

Probably not. Most likely the value of the stocks was reported on his W-2 form in those years as wage income in box 1. If so, the value reported would be the basis of the stocks sold. 

Thomas, I don’t have the W2s from those years. Is there any way other way I could get the cost basis?

You can contact Phillip Morris and ask.  They may not have the records easily available for those years but they're your best bet.

@tchmath 

If you don't have a copy of the W-2 form, you can look up the market value of the stock around the time it was acquired. That can be as easy as doing a search for the company online where you may find a link to historic stock prices. Here is an article from Investopedia that may be helpful on finding historical stock prices. The market value of the stock would likely be what was reported on the W-2 as wage income when it was issued, and that would be the cost basis.