Index the related product price for Tribe events

gistfile1.php

<?php

function index_event_cost( $params, $class ) {
    if ( 'evenementen_prijs' == $params['facet_name'] ) {
        if ( function_exists( 'tribe_get_cost' ) ) {
            $cost = tribe_get_cost( $params['post_id'], false );
            $params['facet_value'] = $cost;
            $params['facet_display_value'] = $cost;
        }
    }
    return $params;
}
add_filter( 'facetwp_index_row', 'index_event_cost', 10, 2 );