add_action( 'manage_post_custom_column', 'price_column_display', 10, 2 );
This line is wrong. I think it should be:
add_action( 'manage_catalog_post_custom_column', 'price_column_display', 10, 2 );
The hook format is as follows:
manage_{$post_type}_posts_custom_column
EDIT:
try your custom column code like the following code. I know in this format it works:
add_action('manage_stores_posts_custom_column', 'sc_stores_manage_columns', 10, 2);
function sc_stores_manage_columns($column_name, $id) {
$custom = get_post_custom($id);
switch ($column_name) {
case 'town':
echo $custom["sc_stores_town"][0];
break;
case 'road':
echo $custom["sc_stores_road"][0];
break;
}
}