Despite the web site name they’re not used parts, this is the best priced place I’ve found in Europe for clutch components. It helps if you can understand German though. https://used-italian-parts.de/advan...tegories_id=85&inc_subcat=1&keywords=Kupplung
Newfren is a good alternative, and often at a fair price compared to O.E.M. Most of us cheap-skates use friction plates originally destined for a wet clutch Suzuki GS650 (1981 - 1983). It's quite an old bike now, so plates might not be so plentiful. Note - the plain plates do not fit.