If anything, I'd expect the prices to be lower. Do you have a local Indonesian equivalent of eBay like we do here in Argentina? Or, just eBay?
I assume "electricity capacity of 900W" means that the wires from the transformer (and in the walls) are only rated for 4 amps at 230VAC. This means that you can't really run a 2000-watt air conditioner at all. Whereas, with an 800-watt solar panel charging a battery, you can run a 2000-watt air conditioner 40% of the time when the panel is in full sun. Washing machines and refrigerators are an even bigger difference, since they usually have huge peaks of current draw when they start up their motors, but relatively low average power. So the solar panels may actually be a much bigger boon than simply comparing 800 to 900 makes it sound like. A single car battery can typically source 6000 watts for brief periods of time.