It is not necessary to purchase a premium theme for a blog, as there are many free themes available for popular blogging platforms such as WordPress. However, a premium theme can offer a number of benefits, including:
Professional design
Customization options
Support
Regular updates
As for the cost of premium themes, they can range from a few dollars to several hundred dollars, depending on the complexity and features of the theme. It’s important to carefully consider the long-term cost of a theme, as well as the value that it brings to your blog, when deciding whether to purchase a premium theme.