buy-one-get-one-free-discount-easy-digital-downloads.php

<?php //do not copy

/**
 * This code snippet checks if there's more than one item in the cart,
 * finds the cheapest product and discounts it from the cart's total.
 */
 
 function buyone_getone_free_discount() {

    $contents = edd_get_cart_contents();

    $cart_items = array();

    if( $contents ) {

        foreach( $contents as $item ) {

            $download = new EDD_Download( $item['id'] );

            $price = $download->get_price();

            $cart_items[$download->post_title] = $price;

        }
    }

    asort( $cart_items );

    $lowest_price = floatval( reset( $cart_items ) );
    $cart_names = array_keys( $cart_items );

    $amount = $lowest_price * -1;
    
    EDD()->fees->remove_fee( 'bogofree_sale' );

    if( count( $cart_items ) >= 2 && ! EDD()->fees->has_fees() ) {
        EDD()->fees->add_fee( $amount, 'Buy One Get One Free Sale ('.$cart_names[0].')', 'bogofree_sale' );
    } else {
        EDD()->fees->remove_fee( 'bogofree_sale' );
    }

}
add_action( 'init', 'buyone_getone_free_discount', 9999 );