What they ^ said.
However, you can post pictures of your husband's knives and ask for identification of them without having to purchase a membership. This is a way to learn if the knives are desirable to collectors and knife enthusiasts and worth further investigation or if they are not.
And then if it turns out the knives have real value you can purchase a Gold membership and ask for valuations as well as sell the knives in the Exchange section of the forum.
To post pictures without a paid membership you need to use a photo hosting site like Imgur.com, it's free. You create an imgur account, upload the pictures from your computer into your account, and then use the BBCode that imgur assigns to each picture to post it here.
To learn more about purchasing a Gold membership click on "Paid Subscriptions" in the blue banner across the top of the screen. A Gold membership costs $30 for one year.