A best bet is to buy
two Twinings of London Earl Grey Tea K-Cup 18-packs for $32 before the above discounts, after. That's $0.40/K-Cup and the lowest total price we could find for this quantity by $5.
$14.40 with free shipping
Update: Of note, the above coupon takes an extra 10% off, not 25% off. We regret the error.