Thanks so much for your kind words! Most of mine I think have come from yun-tech on e-bay: Security Measure
That said - you can pretty much look up “.5mm endmill” (or .6mm/.8mm depending on how fine you really need your detail to be) on e-bay and almost all of the offerings will be from Chinese factories and seem to offer roughly the same quality. I usually go from the ones with “titanium coating” and such, but honestly - the bits are so fragile - they’ll definitely break before you ever “wear them out”. Again, I recommend buying at least 10 at a time, since they’re usually like a dollar each and take 30 days or so to ship.