This model isn't going for 300$ on eBay right now, that's for sure. I check recently sold items on a daily basis. There are certainly a few that have sold for sub 400$, but they are few and far between.

https://www.ebay.com/sch/i.html?_from=R40&_nkw=ASUS+ROG+Strix+GeForce+GTX+1080+TI+11GB&_sacat=0&LH_Sold=1&rt=nc

The first four of mine sold on Offer Up @ 375$ plus 13.99$ shipping.

I can take around $360 shipped if paying via btc or cash app, since both eBay and Offer Up are taking a huge chunk when I use either of them.