You may face a difficult choice, buying a new domain or creating a subdomain.
Pros of a new domain
- If your domain gets banned by Google your domain is not going to be affected while your subdomain and its domain could be affected
- There is no connection whatsoever with the former domain.
- From a legal point of a new domain is like a new entity. This may be important in different jurisdictions with different legal framework.
- The content that you want to add to your new domain may not be compatible with the content of your former domain. This helps splitting up the content in two different entity so that you don’t have to fear that the presence of some content may harm the understanding of some other content on your website.
Cons of a new domain and pros of subdomain
- Every link coming from the main domain are considered to be internal links. Take into account that you get more PageRank from internal links than external links.
- I think pages on a subdomain will rank faster than pages on a brand new domain.
- Your subdomain may benefit from the main domain if it is a famous brand.
- No additional annual subscription to pay for the subdomain
- It is easier to maintain or back up a subdomain because it would be in a folder under the main domain root folder.
- In case of a website for a new language or region, it is going to be a cheap solution to create a subdomain.