Our Breathe Easy group used money we raised to buy them for local surgeries. This was a few years ago now but we used to pay about £70 (this may have been not including VAT), so I wouldn't expect to pay much more than this. The problem if you want to buy one now online is there is a shortage, so many companies are saying 'out of stock' and with anything online now there are delivery delays. They don't seem to be available in pharmacies, so you are looking at medical supply companies.