Need to purchase 2 gpu cards

I need to upgrade the graphic cards on my video editing pcs.

So looked at Radeon since I can put in a ssd and try hackintosh /FCP on 1
And upgrade rest later .

Now msi armour rx570 costs 15600 new.

While a bitcoin mining company has offered 3 used cards for 8.5k each

Is it a good deal?

Someone recently bought a single used gtx1650 6gb for 6500 but didn’t tell his source.