No it is not free.
AB/Rockwell has it.
You dont want it, it cannot be used to program PLCs with current firmwares.
RSLogix 500 Starter is the least expensive alternative.
I have used APS software to upload the program from an old fixed style SLC 500 PLC successfully under DOS. I have tried rslogix 500 before this,but failed.
To do this,you need a DOS PC which have a serial communication port,and you need a 1747-PIC module too.