Generally the cheapest alternative is to buy a Mac when you are or someone you know is overseas.
if it's a desktop, keep in mind they are not covered under International Warranty, whereas Laptops (portable Macs) are.
If you are Importing, a cheaper model (say sub R20000) your savings may not be worth the hassle, but if it's high-spec your savings could be substantial.
Also, authorised Apple resellers are forbidden to directly ship overseas (including Amazon). You can only send to an address within the reseller's country. Which would typically be to a person you trust or a Mail Forwarding service. (I believe there are now a handful of resellers in the US who have arrangements with Mail Forwarders).
Your extra costs will typically be -
Mail Forwarding +$30
Shipping +$200
Tax - 14%