They are expensive once you've added VAT and postage on. Amongst other things I bought the 0.5 "Thins" https://www.engraving-supplies.co.uk/lt404-102-black-0-5mm.html . It is quite flexible though so it depends what job you want to do with it. If you are interested I can send you a small sample to try, it does cut nicely. I don't know what other people have used, the next order I will probably try the ADA signage at 0.8mm https://www.engraving-supplies.co.uk/laser-materials/trolase-ada-signage/ls401-103-black-0-8mm.html