Where can i find the book "and then there were none" by agatha christie on auido online for free?

Your best legal option (that doesn't come with the added threat of viruses and whatnot) is your library's website. Some libraries are now providing online checkout services that allow patrons to go online and check out books in .pdf, audiobook, ebook, etc. online. I suggest checking out the website to your local library (but to do this - if they provide such - you must have a library card).