If someone spends 100 hours coming up with, say a clickjacking vuln, it does not magically make it worth $5000. If someone spends 6 minutes coming up with zero-click sandbox bypass in chrome, its not just worth $5.
Severity matters not time, especially in a bug bounty. If you want the stability (and assurance) of actually getting paid reasonsbly and consistently for this you should get a job as a pentester.
That's kind bad - first of all 50$ can be really low depending on the region, but more importantly this disregards the time spend on looking for exploits that don't pan out.
So I would multiply that 50$ by at least 4.
But still like the other said bugs should pay by severity not by time spent.
