any free theme to use with out creating child theme

You can use any theme without having to create a child theme. It just depends on whether you need to customize it in some way. And even if you do need to customize it, often the theme will have options that you can change, or you can add a plugin that will allow you to add your own CSS.

All of the themes in the WordPress theme repository are free, although some of the themes might offer a premium version with more features. And most of the themes are responsive as well. Click on the Feature Filter link to narrow down the number of themes to go through.