I'm not uncomfortable with eBay. The good thing with them is you get buyer protection, so I think you get 30 days to return it even if the seller doesn't do returns. But make sure to read the fine print. Guys like me who don't want to hassle and have been burned before, I will put on my listings that even though the items are working, consider them as parts only. I don't even mind to take a bit less on price just because I don't want to deal with a return.
For example, one dude bought an AM4 cpu from my gaming rig when I was redoing stuff. Apparently didn't know you should not install a 5800x into an a320 board, installed it, couldn't figure out how to get it to work right, wanted to return it which I let them do. Then I get the cpu back, and it wasn't in the cpu holder correctly and had bent pins on it. So that's why I'm like that about some of that.
That said, I've bought at least 5-6 cards on there and not been burned. Check the description carefully, check the person's feedback. If they have good feedback, they usually care about their rep and will help you out.
When you get the card, install it ASAP and run it HARD. In other words, play on it etc within that 30 day window and make sure it's working correctly so you can file a case with ebay if there are issues. But I've been pretty lucky. My current 6800xt is from newegg, but the previous 4-5 were from ebay. In that case newegg wasn't much more for a new card than a used one on ebay, so what do you think I picked
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