I cant believe people are using basic interest calcs to value...

I cant believe people are using basic interest calcs to value options. Thats completely incorrect, the interest on the strike price may give you bounds, but there are plenty of paramaters to take into account, volatility being the major one. If there is more volatility then there is more chance that the options will move beyond the strike price. There are whole textbooks covering this subject. If you want to see what the value of TOX options should be then download the black scholes calculator from the ASX, plug in all your parameters and see what value you get.

Personally I think its a waste of time, if you think TOX is going up in the short term then buy the options, if not then you shouldnt be buying TOX anyway.