-6x RX 470 4 GB (will cost around $1000)
-Around 1000 Watts Power Supply
-Motherboard consisting of 6 PCI-E slots
-4 GB RAM (cheapest available)
-Least memory-sized SSD
Buying all of this is possible within the range of $2000. You may also check out "Marketplace > Goods > Computer hardware" section of this forums for better deals.
Risk are you can get those as a second hand units, already mining for more than a year already
Like the other user above says, seems its not the right time to buy for new gear
ASIC miner are nearly on full blast
so @OP if I were you, just observe the trend
also there are new GPU hardware coming out soon