Again, let's break down the basics. Styles are a quick and dirty way to instantly change the look of an image by automatically changing the parameters that you'd typically use to get the general look you want. It is nothing more.
In the background, all this means is that the program has a reference setting to use to update the image. When you buy these, you are in effect getting a setting that another photographer used to fix an image, and they saved it to use again later. Problem is that the likelihood of these settings working well for an altogether different image without additional work is usually nil.
Like the Lightroom article before, you can look at an unmodified example of the file format that defines a style. To find default Styles shipped with the application (Mac instructions as I don't own a Windows machine): Open the "application contents" (right click on the Application in File manager to find that option) -then traverse to Resources->Styles folder.
For other user added or example Styles, you'll find them in the users Library folder, then Application Support -> Capture One -> Styles folder.
These ".costyle" files are all text files that you can view in any text editor like TextEdit. I don't advocate changing them.
They don't look much different to the file preset format used in Lightroom, although Capture One appears to have efficiently ignored storing any settings that haven't changed from a default value.
As mentioned before, this isn't rocket science. The sale of these styles as an add-on for huge profit should be seen as a questionable practice in my opinion, especially since it is highly unlikely that any of them will ever become part of your workflow, at least not without further modifications (that you would have done on your own anyway). If you need inspiration, you would probably do yourself a better service to spend time playing with the interface instead.
The annoying thing about adding Styles in Capture One is when you discover that you don't particularly like them, and now you want to remove them. The only way to do this in the application is selecting the one to be removed, clicking that you're sure, and then selecting another. Tedious. I've discovered that you can delete/move multiple styles in the user Library folder and you have to restart C1 to reflect the change. Don't do anything to the ones in the application contents folder!
Half-baked and over sold?