Where I live liquidating GPU's is very easy, 24 hours max. Not as fast as pushing 'sell' button but still quite fast.
No. And you'll lose a fuckton of money doing that. I don't think you've spent any amount of time selling anything online, such as eBay.
Where I live people don't use shitty services like eBay, also living in an area where there are enough potential buyers helps.
I've sold some PC components including GPU's this weekend too. Only cash, only fast pick-up. All gone. No fees.