$tmp_post = $post;
$args = array(
    'meta_query' => array(
        array(
            'key' => 'price_category',
            'value' => '500000',
            'meta_compare' => '<'
        )
    )
);
$myposts = get_posts( $args );
foreach( $myposts as $post ) : setup_postdata($post); ?>
    <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a><br>
    <?php the_content(); ?>
    <hr><br>
<?php endforeach; ?>
<?php $post = $tmp_post;
setup_postdata($post);?>

$tmp_post = $post;
$query = new WP_Query( array( 'meta_key' => 'price_category', 'meta_value_num' => '500000', 'meta_compare' => '<' ) );

while($query->have_posts()):
     $query->next_post();
     setup_postdata($query->post);
     ?>
     <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a><br>
     <?php the_content(); ?>
     <hr><br>
     <?
endwhile;

$post = $tmp_post;
setup_postdata($tmp_post);

$query = new WP_Query( array( 'meta_key' => 'price_category', 'meta_value' => 'До 500 000' ) );