keen for some advice, have some old concrete that I need to dig up out the back (old cubby house "foundation"). digging will be easy with jack hammer/pick/crow bar but wondering how to dispose of it

HArd rubbish has been and gone, have spoken to skip hire places, generally $200 FOR 3X3M but they are $100 per tonne for every tonne over 800kg (I reckon it will be 3-4 tonne all up and not keen on spending $500-$600?)
Any help or advice would be great