Do you know which species of cycad they are? Generally around your area you'd possibly have Cycas media if you're in more of a savanna area. In a rainforest area the possibilities would be Lepidozamia hopei or the much smaller Bowenia spectabilis.

Internationally trafficking of cycads is controlled by CITES regulations and can involve a lot of red tape, if it's approved. Interstate it can be difficult, dependant on where they are being sent. Within your own state it's not usually a problem if they're coming off your own property. However, difficulties can arise for the purchaser if they are confronted by the authorities and have to prove the plants were acquired legally. That's where it would be best to check with the Dept. of Environment and Heritage Protection. They could tell you how to do it and avoid legal complications further down the track.

You probably have the legal right,but you know digging them up is like stealing from your heritage? Sort of like being the keeper of the last two Dodo's,and then ...cooking them.
Now,if you collected some seeds- and even those don't sell cheap- you could have forever income compared to right now income.
Its kind of awful you would have so many magnificent plants..and want to get rid of them.