What are you wanting to do? Pumice is similar but better in many ways than perlite, but more expensive. Pine bark pieces can be used effectively.

Starting a vegetable container garden on my patio. On a fixed income, so the potting mix is very expensive even at Walmart. Looking for perlite alternatives.

Coconut core, you buy it dehydrated in a block and then rehydrate it with water it's the best and good price

If you have a Menards nearby they are the best for potting mix that i've found - the promix bales are about double the size of anything else i get.