Id toss on ebay starting at $500 and hope.

As odd as it is, look on ebay as there seems to be a surplus of hemi pistons. In many cases I can buy hemi pistons cheaper then any forged 318 or 360 pistons.

Its a bit hit and miss but many sets of even some of the most modern pop up for $500 and below if you watch them.

Here are a couple examples... wisco and BME... A smart shopper knows $500 and under is very easy to find.