Aside from the fact that a lot of work that goes into making a SSC, materials are not cheap and a good carrier uses premium fabrics and hardware. Carriers like the Scootababy and Ellaroo are not mass produced in the same sense that many of the more commonly available brands are - they are not produced offshore in factories in countries that have very cheap labour. (Not that it helps make it any more affordable, just a bit of explanation of why good carriers are expensive).

Though, if you compare the cost of these carriers to a Baby Bjorn (for example), they are actually not that much different in price, especially when you consider the longevity of wear that you will likely get in comparison to a Bjorn.

The USD - AUD exchange rate is pretty favourable right now too, and with the US economy depressed it's not difficult to find a bargain if buying second hand from US sites like thebabywearer. International postage can be a bit of a stinger though.

If you sew, a ring sling can be made quite cheaply.