First of all, thank you for the fast answers.

Second of all, LOL I kinda saw this coming. But that's currently the price of RX580's over here right now. And actually it was even more when ethereum was $1500. Then after it crashed, prices went down and this is the lowest they got. I kinda feel it's gonna happen again, prices for GPU's will again go up. It already started over here.

And there is no really other cards to buy, I wanted 1070's too, but it's like $200 more comparing to RX580.

While 4GB versions od the same 580's are alot cheaper, same goes for 470's, 480's, 570's but I don't know if those are as good as 580's? Because so far I have experience only with 580's. And should I even build a rig with the 4GB cards, I know those cards are safe for like a year and a half or two from now mining ether, but speaking about resell price if i want to upgrade etc?