If you're only buying 1 pair of shoes, then yeah, it gets pricey. But if you can get a group together to order above the minimum for flat rate shipping, it's not too bad.
retailmenot.com also nearly always has some sort of coupon code.
I ordered a few things a few weeks back. They had some big sales on with clearance items and the like. Clearance items were 20% of the already discounted price. Most things were already discounted by 50%. Use the $20 off coupon that they usually have from the above site and it erases a good portion of the postage costs, then all the other sales means you're well in front. Depends if the thing you want is on sale or full price. I got a pair of shoes, 4 shirts, 4 pairs of shorts, a singlet top and 3 pairs of socks for just over $300AUD.