Custom metabox does not store data

Are you sure it isn’t saving the values to the DB? Perhaps it’s just not displaying the previously saved values in your form?

$values = get_post_custom( $post->ID );

This is what you are using to get your meta – but this returns a multi-dimensional array. Therefore when accessing your beef_meta_box_price value, you need to use $values[‘beef_meta_box_price’][0]. Alternatively, replace get_post_custom (which returns all meta for the post) with get_post_meta:

$beef_meta_box_price = get_post_custom( $post->ID, 'beef_meta_box_price', true );

This way you don’t get an array, just a string.