For 2000$, what you need, CPU, Memory, GPU,
I7-6700K - 320$
ASUS Hero 8 - 230$
GSkill Trident Z F4-3000C14D-16GTZ - 120$
Samsung 850 EVO 500GB - 150$
EVGA 750 G2 - 100$
GTX980Ti Classified 460$
xxx
With this you have around 600$ more.
You can buy ASUS PB287Q 4K 28" for 480$ and In Win 830 case for 85$,
And you can find somewhere 160$ and instead 980Ti Classified to buy GTX1080 Windforce for 630$.
I search Amazon as you say.
Where is your case, PSU, keyboard, mouse, monitor?
When I buy new stuff I try to sell old and save for something.
I was sold my old Z77 platform and I will buy Samsung 850 1TB SSD and gaming mouse later.