Wait for KAWPOW. Just 3 more weeks.
KAWPOW will be nvidia ground.
1070ti/1080ti/1080 and tons of 1060 3gb
amd will be competative only on vegas or higher compute gpus.
those 4gb amd is by far more than even 100% emission of raven could supply.
so currently there is no option for them.
i predict 15-20$ per 470/570 4gb in august.
No they will never be that cheap.
I from time to time sell some of my mining GPUs that I got back in 2013-2014 like the R9 270X and the R9 280X and those even fetch around, $35 and $60 respectively.
There is a bunch of these RX 470 going for $60 currently and most likely the price won't go further down. There is still a demand for them for people who want to do rendering or gaming.