USB flash drive warranty repair?
 

Tell me pls, my usb for some reasons my usb doesn't work. Maybe exist warranty repair for that problem???

Pfft. These things are disposable these days. Odds are, you're warranty required you to pay the shipping. That's about $3 for something worth $10. It's only worthwhile if the stick was large, like 128gb. Those are about $25.

But warranty aside, try it on another computer. Verify the flash drive is at fault.

I just want to know. may I do it absolutely free

These local USB drives aren't reliable and will last only few months or days.