Dual GPU setups seem to be falling out of favor lately due to lackluster support in games, and crossfiring two low end cards has never really been recommended. Also, the 2nd PCIe x16 slot on that board is only PCIe. 2.0 x4, so bandwidth is equivalent to PCIe 3.0 x2. Not optimal.
I would recommend getting a single, more expensive card than two cheap ones. It sounds like GPU mining (which has been driving up prices for mid range cards like RX 570/580, GTX 1060) has taken quite a hit lately, with a bit of luck they'll start being available at reasonable prices soon.