B&H Photo has Seasonic Prime Ultra 650W power supply $79.99 after rebate. Shipping is free and there is no TAX outside NY.
https://www.bhphotovide
There are also other models on sale.
FOCUS 750W 80 PLUS Gold : $84.00 after rebate
https://www.bhphotovide
Focus Gold Series 650W 80 Plus Gold: $53.20 after rebate
https://www.bhphotovide