Value of Query string [closed]

If those values are in your query then you can use the following

if( get_query_var('total') ) {
    $total_value = floatval( str_replace( '$', '', get_query_var('total') ) );
}

or else

if( isset( $_GET['total'] ) ) {
    $total_value = floatval( str_replace( '$', '', $_GET['total'] ) );
}