Kildwick EasyLoo Composting Toilet with Fan 5V, 368,90 €
Check out KILDWICK.com for some awesome d.i.y. kit's or already assembled composting toilets. They come with everything you need for less than half the cost of the leading Natures Head toilet :
Dry – Compact – Remote Composting - WORLD OF COMPOSTING TOILETS
Kildwick Klassic Urine Separator Diverter for Compost Toilet - White : Amazon.co.uk: Sports & Outdoors