As I always say whatever someone is willing to pay... There's one ms70 that someone wants $320 aud for And there's one ms70 for $163 aud in the USA which is where the market for these coins are so I would say in the Aussie market between 120 - 150 if your lucky But that's my opinion and if you own one looking to possibly sell your probably feeling insulted right about now but not many people in Oz collect elephants and I know from having afew rolls and trying to sell them in the past...
An auction is the only way to find it's price, & as Silvertounge15 said above, "It's worth whatever someone is willing to pay." Auctions can get manic - Therefore the question is...How bad do they want it?