4 Ct Gillette Venus Embrace Razor Blade Refills, $4 Amazon Add-On

$4 with $5 off coupon.
Coupon also applies to other Venus refills, but this is the best deal IMO.
https://www.amazon.com/gp/product/B001LPBUUC/
If I’m not mistaken, these blades are the same as these more popular ones here at $16.79 ($5 off also applies): https://www.amazon.com/gp/product/B0013MTHWQ, just different packaging.