I bought some typewriter ribbons from AliExpress...

So... I bought 4 blue ribbons and some black/red... I tested only blue so far, but my concerns about B/R are a fact.
To be honest I searched for the cheapest... But also all of them look alike on the pictures so I don't think there is many different products out there.

 Probably there were some warings on the net/typoshpere already - but I didn't look any advice on that purchase. My bad.