Edit: This is for the Cellular/LTE/4G whatever you want to call it model - NOT bluetooth only. RRP is $649 from Samsung
Pretty simple, $23/month for 24 months,
No interest, no early payout fee's. The deal online states you need to be with Telstra, however this is not true if you head into a store.
I had previously had an account with Telstra, so was a little easier for me, but they will set you up with an account number and then add just the watch.
Once the firmware updated, managed to get it working with fine Optus.