If test tubes were your thing, and you wished to scale up your propagation operation, a pack of test tubes and a rack would do the job inexpensively. You could store your seeds this way too.

Plastic is fine, and there’s no need to be sterile or RNase-free. Polypropylene is durable and translucent, clear enough to monitor root growth. Polycarbonate is crystal-clear, but somewhat brittle and could crack when dropped.

I’ve standardized on 15 mL and 50 mL tubes, and properly-sized racks to match. 15 mL tubes are small and dry up quickly, but they could be used to splint irregular-shaped cuttings. They’re also a good size for seed storage. 50 mL tubes provide more than enough room for most cuttings. Self-standing centrifuge tubes are convenient because they could be used temporarily without a rack, but I’d still highly recommend a rack for long-term use to mitigate the tipping risk.