Why don't you make it yourself.
I am serious it is really simple to make a compost bin and start throwing the everyday rubbish like the vegetable peels, food etc. into this bin. In a weeks time your composting will start and you can use that in your garden....
You can also get some vermiculture bins that have earthworms in them that help speed up the process of composting...
the best thing is you will be doing it yourself and it will be 100% organic...