I have found that Poggio Spelt milk from Woolies is a much nicer alternative to all other alternative milk products and I've tried a lot of them. I hate Soy, Rice milk is ok and Almond milk just overpowers my coffee, Weetbix and anything else I need to use milk for. This is probably as close to skim milk without being milk as you can get. It isn't too sweet or have an overpowering taste so can be added to anything. I like making lattes and flat whites at home and I can still actually taste the coffee.
The Barista Soy milk which is tolerable for coffee is normally around $4. Soy, Almond and Rice milk in general goes for about $2-$4 so instead of buying any of these, give this a try instead.
It's usually expensive at $4.69 per litre and regularly goes on special for $3.99 per litre but at the moment it's selling at 2 for $4.68. It can be found in the long-life milk section. Shelf life expiry varies, my current purchases have the expiry ranging from 14/8/15 to 24/12/15.
I don't normally have Lactose free or Goat's milk either due to having an allergy to animal sourced milk.
Have you tried Coles branded lactose free milk? From memory it's $2/L and it does the job well enough. Would be interested in a comparison.