Any idea what a hot compost bin costs?

A quick internet search shows me various prices ranging from £400 for 600 litres to £199 for 200 litres.
Well this one is 1.5 cubic metres which is 1500 litres and has cost next to nothing.
Pallets are free, covered with polypropylene protective sheeting at £5.60 a sheet (one sheet covers two sides of a pallet) and fillled with recycled polystyrene packing peanuts at 6p a litre (it takes about 100 litres of packing peanuts to stuff a pallet)
4 pallets clad and stuffed plus one square of expanded polystyrene sheet similarly clad with protective sheeting. Total cost about £60