Can i use premium Themes and Plugins on free hosting?

[Hamzao01]

Hi,
I'm a developer and use different websites to create testing websites. But now i want to convert one of my free hosting website to regular website. I have some questions regarding this:

1. Can i use premium themes or plugins on my free hosting website?
2. Shall i upgrade this hosting package or change my hosting account?
3. Shall i start new website, instead of continuing this one

I want to build website like this website, can i do it with free theme?

Kindly give yourbest suggestion which should help me

Thank you