Is there any current advertments running?
Does this site have any revenue?
How long has this site been up?
Is the script you are running custom?
If you answer some of these you will probably get a better more specific answer to your question.
Without those answered I would consider this site turnkey running a freescript. So I would probably pay no more than 30$ and that would be me being quite generous.
I found an error on your site. If you press "Host it" and then press back on your browser, the little animation will always run. The only way to fix it is if I refresh the page.