My softbox using those flex rods similar to those tent rods you can grab at winnings shop/carrefour. If you want to DIY, maybe can try.
I don't know if the jinbei's one is the same or if the rods will fit the speedring, but you can try asking those shops on the tents or just buy a cheap 2 men tent from giant/carrefour and use those rods? Shouldn't cost more than 20 bucks with the tent but length may require some cutting.