MyNetFone are having a sale.
They have heaps of their voip products available at a reduced rate, with free express shipping and $20.00 free calling credit with each item purchased.
The best deal they have is the VMNF100LD Analogue Telephone Adaptor which is on sale for $19.95, with RRP supposedly $99.95. This deal's good because it has free express post AND you get your $20 call credits. So you can gain 5c in a way. :/
The sale ends at the end of June. Check out the other deals there too.