I think you're trying the right things so far. Total Photographics in Kent Town usually has a few used enlargers in the back room, but it's rare that they'll have anything capable of 4x5. As to your budget, enlargers can be priced with big variation; some sellers still want the big bucks, some people are just happy to get rid of them, getting one for the right price is a matter of luck and persistence.
Originally Posted by TimF
Another suggestion is to keep an eye on the local auctioneers, such as MGS etc. They usually list their upcoming items on their websites.