It just occurred to me that it may be cheaper to drive an LPG-powered Camry than a petrol-powered Yaris. So I did a quick search to find out the manufacturer's specifications. The Camry is spec-ed at 14lit/100km for town driving (and about 40% better for long distance), while the Yaris is spec-ed at 6.1lit/100km.
Translate that into running cost: At the low point of the week, LPG costs 49.9c per lit, while unleaded petrol is 117.9c per lit. Hence for Camry, that works out to $6.99/100km, while it is $7.19 for Yaris. It does not take much imagination to figure out that after gas conversion, the Camry will still have much more boot space than the Yaris.
So, to all you guys out there who want to cut costs, it is time to make the switch. I could be wrong, but I don't think there is an LPG conversion kit available for Yaris.