Very nice. If that were a single natural smoky quartz crystal, we would call it a "terminated" crystal and you might expect to pay around £400 ($520) for it. Unfortunately it isn't. It's a massive piece of partly-gemmy smoky quartz which has been cut and polished to artificially create a terminated point. Likely from Brazil, I would have thought. As such, I wouldn't expect it to be worth more than a quarter of that, although you may find similar items being peddled by new age/spiritualist sellers at inflated prices.
I see similar items rather frequently. Red-Coat is 100% spot on in his assessment. Even these cut and polished pieces retail between $300 and $500 as most rock shops I visit. Personally, I think you did ok on the price, as long as you like it.