Hi, this looks like just the plugin for me, am looking to search based on a price range as per your example however I'm getting errors and haven't managed to get this working.
The error appears when I add
function my_queryable_custom_fields() {
register_queryable_custom_field( 'price', array(
'numeric' => true
) );
}
add_action('init', 'define_queryable_custom_fields');
to my functions.php I get struck with...
Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'define_queryable_custom_fields' was given in **MY URL**/wp-includes/plugin.php on line 395
not sure what to do from here?