So, FFX/X-2 HD was released
$29.99 list price with a 20% discount making it $23.99 (as is normal for SE's games, discount as release).
But GMG made a pricing error. They set the list price as $23.99, with an additional 20% release discount, making it $19.19
And, their 20% off coupon, and apparently their 25 % coupon, both stacked on that.
So in the end, for a short time after release, you could buy the game for 15.35 (if you used the 20%) or even 14.40 (if you used the 25%)
The mistake was fixed shortly after it was released. But I was able to pick up a key for $15.35. Well worth that price for two full RPG games with many hours of gameplay.
But their mistake basically let you triple stack a 20% discount, or two 20% discounts and a 25% discount. You can still get something like $19 on GMG though.
Can't sleep, clown will eat me.