TCP Category Subdomains plugin can converts post and product categories to sub-domains. Simply Create a Posts or Product Categories. All post and product categories will be included inside the plugin page. You can choose to enable or disable them. You may require one time Configuration of adding Wildcard Sub-domain but most of the Host already did it. It will increase the performance of site. Also it will help in SEO.
Do not forget to setup a WildCard Subdomain.