Remove zero cents ".00" from Easy Digital Downloads.

edd_format_amount_decimals.php

<?php

function rm_edd_format_amount_decimals( $decimals, $amount ) {

    if ( floor( $amount ) == $amount )
        $decimals = 0;

    return $decimals;
}
add_filter( 'edd_format_amount_decimals', 'rm_edd_format_amount_decimals', 10, 2 );