I might have bought in packs of 50 - seemed cheap when also buying a Festool sander and vacuum
They are about 60p a disk but all the reviews I see suggest that you shouldn't be put off by the price as actually a metric such as price per cubic metre of wood removed (or similar) is actually cheaper than some of the cheap sanding disks. There is an argument that the price per wood removed is the only relevant metric, but I would also argue for speed of removal as I prefer to spend a little bit more to buy time and am fortunate to be able to do so - on all the metrics the cubitron did well and my friend who lent me his vacuum and sander to try also lent me xtract cubitron disks to try and they are superb
sanding disks from Amazon
all other bits from D & M Tools - who were superb to deal with - as well as being a very good price I ordered and an hour later realised I had bought the wrong vacuum(the battery one when I wanted corded!) I phoned them back, they answered almost instantly and the chap sprinted over to the warehouse and was in time to remove that box and replace it with the correct 240v version. As they were also doing a deal with the 240v version and the bluetooth remote he then refunded £12.99 - quite impressive as I had already received the DPD notification that they were on the way to collect my items! All sorted smoothly and very graciously considering I was the one who messed up - though as he said, easier than my having to return items!