Seagate Firecuda 8TB 7200RPM 3.5" SATA ($400 - $60 - $120 coupon = $220)

Firecudas are only a bit faster than Barracudas, if you want cheap then wait for the benchmark $20/TB sale price. Yes they are CMR unlike 8TB SMR barracudas but if you want good performance and price per TB all at once you should be going for 10TB+ anyway.