I'm not sure if you can directly buy the 'Euphoria' visual novel. In some regions, visual novels with certain themes may be restricted or not available for purchase due to content regulations. It also depends on the platforms where it might be sold, such as Steam or other digital distribution platforms. They have their own policies regarding the types of content they allow to be sold.
As of my knowledge, the 'Euphoria' visual novel has some rather extreme and controversial content. Many mainstream platforms would not sell it because of their content policies. However, there might be some less - known or unregulated channels where it could potentially be available for purchase, but this comes with a lot of legal and ethical risks. Also, in a lot of places, this kind of content is not acceptable and would be considered against good taste and decency.
It is difficult to simply say yes or no. 'Euphoria' is a visual novel that may contain disturbing and inappropriate content. Some countries or regions have strict regulations on such content. Even if it is available for purchase in some places, it may be banned in others. And not all stores or platforms will carry it.