Get minimum for free shipping set in WooCommerce settings

wc-get-free-shipping-mininum.php

<?php
/**
 * Get free shipping minimum
 *
 * @param  string $zone_name Zone name.
 * @return int $min_amount Minimum for free shipping.
 */
function get_free_shipping_minimum( $zone_name = '' ) {
	if ( empty( $zone_name ) ) {
		return null;
	}

	$min_amount = null;
	$zone       = null;

	$zones = WC_Shipping_Zones::get_zones();
	foreach ( $zones as $z ) {
		if ( $z['zone_name'] === $zone_name ) {
			$zone = $z;
		}
	}

	if ( $zone ) {
		$shipping_methods_nl  = $zone['shipping_methods'];
		$free_shipping_method = null;
		foreach ( $shipping_methods_nl as $method ) {
			if ( 'free_shipping' === $method->id ) {
				$free_shipping_method = $method;
				break;
			}
		}

		if ( $free_shipping_method ) {
			$min_amount = $free_shipping_method->min_amount;
		}
	}

	return (int) $min_amount;
}