If you want a modern (and official) reproduction of this, it will cost you £432. But this vintage Louis Poulsen PH5 Pendant Lamp by Poul Henningsen is currently on eBay for a small fraction of that price.
The lamp dates back to 1958 and is a bona fide design classic, used widely in both civil buildings and in the home, especially as a light over dining tables.
This is a vintage model, said to be from the '60s and original except for being rewired with new braided silk for the flex. Condition is described as 'very good' and has the correct 200 watt ceramic bulb holder as per the original design, as these fittings can take a 200 watt bulb (if you can find one, although one is supplied initially). You can also use low energy bulbs and lower wattage standard bulbs too.
If you want it, the bidding right now is £1.24.