Walmart.com has Intel Core i5-6600K 3.5GHz Quad-Core Processor (BX80662I56600K) on sale for $231.92 – $61.49 when you select free store pickup = $170.43 (price updates during checkout). In-store pickup must be selected for the discount to apply.
This is a overclock-able processor with stable 4.8GHz (with right hardware), without delidding.