FacetWP – index EDD variable price

<?php

// Add to your (child) theme's functions.php
add_filter( 'facetwp_index_row', function( $params, $class ) {
    if ( 'price' == $params['facet_name'] ) {
        $price = edd_get_lowest_price_option( $params['post_id'] );
        $params['facet_value'] = $price;
        $params['facet_display_value'] = $price;
    }
    return $params;
}, 10, 2 );