Looking for 2 controller boards to replace the dead ones I have

Thank you

i currently have a r9 270 and getting 435kh/s .. iam looking to build a 4 card rig with r9 280's but really cant find ant good prices and when i do they are sold out .. i can find the r9 270's pretty easy for around $200.00 .. can anyone help me out so i dont over pay