before I start buying it

I want one demo thems this https://ebullient.qodeinteractive.com/
to try it to see if it is ok for my site
before I start buying it thanks

Unfortunately that is not how things work - the demo of the theme as per the link you shared is the closest you will get

thanks,
YES, AND HOW WILL I KNOW THAT IT SAYS THAT IS THE ISSUE

Sorry, not sure we understand that question.

There are some (very few) authors who offer demo site solutions however it is rare, even though that theme is from one of the biggest and most respected author on envato

ok thanks