Buying stock from employer before going public

Hello! My husbands company he works for was purchased and it has been announced they will go public. It has also been announced that it will be offered to employees at a lower price but we don’t have any details yet. I’d like to start saving to buy some but not sure how much is needed to buy to really make a difference in our investing. Has anyone done this before? What’s the best way to optimize the opportunity?
Thank you!