A best bet is 10 pairs of Victoria's Secret Women's Hiphugger Panties in 48 colors (Rainbow Stripe pictured) for $52. With free shipping via the above coupon, that's at least $34 off and the lowest total price we could find. They're available in sizes XS to XL, although not in all size/color combinations.
Have a larger order? Coupon code "30OFF150" takes $30 off orders of $150 or more. (It stacks with the offers above.)