tcpteam

TCP Category Subdomains plugin can converts post and woocommerce 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 configuration on adding wildcard subdomain. Normally it will be configured by host, ask them if needed. It will increase the performance of site and will help in SEO. Plugin will also auto redirect to new subdomain link to avoid duplicate content issue.
[FREE] Maximum 5 post or product subdomains 
[PREMIUM] Unlimited subdomains for all post and product categories
Upgrade to <a href="https://app.thecartpress.com/plugin/tcp-category-subdomains/" rel="nofollow ugc">PREMIUM</a> to enjoy unlimited domains.
IMPORTANT 
Don’t forget to configure WildCard Subdomain.
<h3>Donations</h3>

Category Subdomains for Woocommerce by TheCartPress

TCP Category Subdomains plugin can converts post and woocommerce product categories to sub-domains.

hazardcell

There seem to be some issues with this plugin and WordPress MU 2.8 so please ONLY USE IT WITH 2.7. I doubt I will be updating this plugin anytime soon. If you do manage to patch it and want to make it available to the public, email me and I will include it for you
This plugin turns a vanilla WordPress MU install into a subdomain forwarding site. It gives each user a subdomain and allows path forwarding to an external site, a hosted blog and/or a hosted profile. Meta tags, keywords and path forwarding to external sites are all supported.
Users should go to Dashboard->Subdomain to edit subdomain settings and activate/deactivate the blog and profile. The public profile can be edited at Users->Public Profile. The admin for the plugin is at Site Admin->Subdomain Forwarding.
Please read the FAQ and Known Issues/Limitations sections before installing the plugin.
<h3>Known Issues/Limitations</h3>
As this is a very early version there are a couple of minor issues that haven’t been overcome yet:
<ul>
<li>Users with blogs who try to login from the main site will have to login twice before they can access their control panel. This is due to some issues with the cookies that I have not been able to deal with just yet.</li>
<li>The username field will be used as the subdomain. Users cannot yet choose a custom subdomain name.</li>
<li>One user can only have one subdomain. Multiple subdomains are not supported yet.</li>
<li>This version will only work with one domain name. It has not been tested on sites that have been setup with more than one domain name.</li>
<li>This plugin works with VHOST installs only.</li>
<li>Users will have to sign up for a normal account before they can get a blog.</li>
<li>I’ve only tested this with clean installs so I’m not sure if it will work with a current install without modifying the database in some way.</li>
<li>Currently, only users who sign up after the plugin is installed will get a subdomain. Again, I do not reccommend installing this version on a current install as it could cause problems.</li>
</ul>

WordPress MU Subdomain Forwarding

There seem to be some issues with this plugin and WordPress MU 2.8 so please ONLY USE IT WITH 2.7. I doubt I will be updating this plugin anytime soon …

Category Subdomains for Woocommerce by TheCartPress vs WordPress MU Subdomain Forwarding