Seems the only way to have aircon is to get something that will dry the air in a room. Any DIY solutions typically involve air being forced over something cold like ice. There Will be a lot of effort and mess if you use ice, not to mention the cost of making ice is more than an aircon.
Aircon units can easily be bought for 8-9k. The true cost is the electricity which is over 12 peso per kilowatt hour. If you dehumidify a room and keep it well insulated then a fan will work wonders.
You could also sit in a small kiddy pool to keep cool. Assuming you have a water source.
The cheapest solution is to move to a mountain area. It is really cooler up the mountain.