I buy tyrolit discs from abtec abrasives who do bulk buy deals, think they're about 60p each for 125mm discs when buying 50 and they seem to last better than the bosch ones I was using before
I got one of the diamond disc packs from Aldi (or lidl - cant remember) and its been superb. Ive been using it for ages (stone, concrete, ceramics - not metal) and its still good. I think theyre back in stock on the 28th, so i should get more, just in case this one eventually wares out.
This is dry cutting. I bought a makita disc for my husky 2stroke a while back, and was so unimpressed. If the aldi ones came in large size, id buy them for the 2 stroke also!
As above though, ive found the thin discs to be rubbish. Id rather buy bosch ones from trago for 50p / unit any day.