OptimMore via Amazon offers the OMorc Unisex Graduated Compression Socks in Black for $9.99. Coupon code "TKTBJ8AS" drops the price to $7.99. Plus, Prime members receive free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping adds $6.49.) That's $8 off list and the lowest total price we could find. They're available in sizes S/M or L/XL.
Need more than one pair? Also available is the OMorc Unisex Graduated Compression Socks 2-Pack for $14.99. As above, Prime members receive free shipping. That's $7.50 per pair, $18 off list, and the best deal we could find.