This is a very cheap low-power air-con unit

Step 1: Materials

2 plastic containers and 1 lid ($10)
1 mini fan ($10)
Enough Water Balloons to fill the container ($0.15 each)

Step 2: Cooling Component

As cooling components im using frozen water balloons. Regular ice works fine but it melts and dealing with it becomes messy. The water balloons make it super easy to recycle, just toss them to the freezer and wait.

Step 3: Vent Holes

On one end if the lid see you there a circular hole roughly the same diameter of the fan. it can be bigger or other wise the fan wont be able to hold on to the lid. also having gaps will allow the warm air to escape losing efficiency.

on the other end of the lid cut a rectangle shape hole for the cool air. you can cut 3 edges of the rectangle and use the plastic flap to control (a little bit ) the direction of the cool air

Step 4: Put Together

Stack the containers and put the water balloons, ice packs or regular ice inside. The second container is to catch the condensation. without it it will work but there'll be aircon piss all over the place.

Put the lid on, fit the fan on one of the vents and open the second vent so the air can go out.

turn on the fan

wait a few minutes and the temperature of your room will drop slowly. ( the smaller the room is the more efective the unit will be)