ETH on!
As of today, June 3 ETH is currently $221, so to get $2k a month mining this coin your going to need >500MH/s of hashing power to generate it. With a Radeon RX470 that I use for mining Zcash you can easily squeeze nearly 30 MH/s out of it - with BIOS mods and overclocking tricks.
First find a really cool place - this is essential - my last Zcash mining rig super-heated my old flat to 57C/134F! - it was worse than the Libyan desert I backpacked in many years ago - illegally of course!
The highly rated Radeon R9 390
Setting sail
For our >500MH/s about 14 cards should do the trick. The cost of this expedition will be around $5k including the motherboards, power supplies, RAM etc. to run the thing. This is also assumes you can buy cards in this number as they are rarer than hen's teeth - try eBay for used cards too.
$5K is a lot of cost to recoup, and it is possible to buy pre-assembled rigs on eBay, but you'll pay a premium cost for that luxury.
In essence by month 2.5 you'll be in profit happily making Ethereum profits - assuming the difficulty doesn't rise too much. Also note the fact that Ethereum is moving from Proof of Work (PoW) to Proof of Stake (PoS) by the end of this year.
Happy mining!