There are several ways to find products.
If a manufacturer has a website, I would start there to see if mail order is possible. They may also tell you where it is distributed.
In addition, our website has a "biz directory" (tab on top of site) of California dispensaries and you can link to most of their menus on-line to determine their catalog of products. Additionally there are product reviews and links to sellers on sites such as Leafly.com