I believe generally in modern engines you don't want to be running mineral oil or mineral oil blends. Your basic synthetic oils aren't expensive, and are decent as long as you get a decent brand (Penrite, Nulon etc), and also Gulf Western (syn-x 6000 is a really good and good valued oil suitable for the car if you can find it).
I believe Mitsubishi call for a 5W oil.
Nulon:
5w-20 (primary)
5w-30
5w-40,
Penrite:
HPR 0 0w-30 (primary)
HPR 5 5w-40
Castrol:
Edge 5w-30 (primary)
Magnatec Stop Start 5w-30 (I wouldn't go this one, unless high mileage)
Gulf Western:
Syn-x 6000 5w-40 (probably the best value, and is a great oil if you can find it)
SYN-STAR LV 0w20
Mobil:
Note that I had to google this one, it was the only one that didn't seem to have a proper lube guide. I would therefore take this with a bit of caution. Their main Australian site seems to target European brands now.
Mobil 1 0w-20
Super 3000 0w-30
Mobil 1 0w-30
Super 2000 5w-30
Mobil Formula S 5w-30
In each brand the recommended is at the top, then the lower ones are recommended in descending order. The common theme amongst these is that they're all synthetic. I guess another way to look at it is using any of the recommended oils from the different oil companies if there is a warranty issue you should be okay. If you decide to use some semi-synthetic oil not recommended to save $10 at every 15,000 km you may end up with warranty issues if something arises.
No offence to aspir3, you have to consider his car is a 2008 model? There was a change in the 2.0 L engines around 2012. For instance, for a 2008 Lancer Nulon recommend the 5w-30, 5w-40 fully synthetic, and last on the list is 15w-40 semi synthetic. The last is for extreme wear situations where you are burning oil. For the older pre-2013 2.0 L Lancers, penrite still recommend HPR 5 primarily, with their high end fully synthetic in the middle, and lastly their 5w-40 semi-synthetic. Remember that is only under pre-2013 Lancers, and would be for high mileage engines where it is burning oil.
As you can tell, I just wouldn't recommend trying to save $10 a year on cheapening out on oil
I would suggest this one:
https://www.autobarn.com.au/gulfwestern ... 00-5w40-5l