I used Interparcel to ship a 20" alloy wheel with tyre. It was through UPS's service, and cost around £25 I think, (with insurance).
Great service with no problems
My BMW Miniature Collection: http://www.bmwcollection.co.uk
Past: E92 LCI 325i M Sport | F10 523i M Sport | E90 LCI ///M3 | E60 LCI 525i M Sport | E92 330i SE | E60 LCI 525d M Sport | E39 530d Sport | E65 730d Sport | E90 330i M Sport | E39 525d Sport | E46 320d Sport | E46 325i Sport | E46 320d SE