I had found the older X1900 All-In-Wonder cards for about $225, but everyplace was backordered. In stock cards were priced between $350 and $450. Often you also needed a larger power supply as well.
There is a new X1900GT card that uses 36 pixel shaders for about $200 on sale. I do not know if that card will work (it should) but it won't be quite as fast.
What's a 'larger power supply'?