I have had one for about 3 years. I only use it for an hour or so, early on a winters morning. They are very cheap to run, and work well when they have a comparatively small area to heat. I have mine next to my computer desk.
They are repairable but as they are so cheap to buy, its hardly worth it. Even if one bulb has blown, its still possible to use the remaining 2.
I can't recall where I bought mine...probably on ebay.
I have just had a look and they are available for about £12-£13, including p+p.
As they are so cheap, its got to be worth having a punt !