Simple Aquaponics is a very simple system which anyone can afford. It uses very little water and can produce a lot of vegetables and fish. The fish poo in the water, and the poo is food for the plants. The plants clean the water and it flows back to the fish.
There are two types:
A simple plastic sheet and a bucket
This is the simplest form invented by Afriponics. Simply dig a pond and throw the earth to one side. Put a plastic sheet into the pond and also over the earth you dug out. Now you have a deep side in which you put your water and fish. On the high side you put pebbles or small rocks in which you put your plants, your grow bed. Now every hour or so take a few buckets of water from the pond and throw them into your grow bed.
The course sand makes a very good and cheap grow medium. The depth of the pond is approx 1m. It will support a maximum of around 100kg of fish or 100 fish to 1kg or 200 to 0.5kg
A bit more advanced method is to connect three blue plastic drums and use a small solar pump to pump the water.
You can find detailed instructions here.