auto-coupon-woo.php

add_action( 'woocommerce_before_cart', 'apply_matched_coupons' );

function apply_matched_coupons() {
    global $woocommerce;

    $get1 = 'getonech'; // your coupon code here
    $get2 = 'gettwoch'; // your coupon code here
    $get3 = 'getthreech'; // your coupon code here
    $get4 = 'getfourch'; // your coupon code here
    $get5 = 'getfivech'; // your coupon code here

    if ( $woocommerce->cart->cart_contents_count >= 1 && $woocommerce->cart->cart_contents_count < 2 ) {
        $woocommerce->cart->add_discount( $get1 );
        $woocommerce->show_messages();
    } elseif ( $woocommerce->cart->cart_contents_count >= 2 && $woocommerce->cart->cart_contents_count < 3 ) {
        $woocommerce->cart->add_discount( $get2 );
        $woocommerce->show_messages();
    } elseif ( $woocommerce->cart->cart_contents_count >= 3 && $woocommerce->cart->cart_contents_count < 4 ) {
        $woocommerce->cart->add_discount( $get3 );
        $woocommerce->show_messages();
    } elseif ( $woocommerce->cart->cart_contents_count >= 4 && $woocommerce->cart->cart_contents_count < 5 ) {
        $woocommerce->cart->add_discount( $get4 );
        $woocommerce->show_messages();
    } elseif ( $woocommerce->cart->cart_contents_count >= 5 ) {
        $woocommerce->cart->add_discount( $get5 );
        $woocommerce->show_messages();
    }

}