What would be the cheapest, yet, still legal

, way to send a package of Amiga goodies from UK to Serbia, Europe ?
Size and weight are that of a classic wedge Amiga box with internals.
My UK contact is a great guy, and he really tried to find the cheapest way for sending this, but all he could come up is 45-50 quid. DHL is almost 100 quid ?!?
Any advice or comments would be appreciated
