Usually partner discounts will say something like "up to $20." The amount of the discount depends on which product edition is chosen.
Is it PenFed Credit Union? If so, their member discount page does say "save up to $20 on TurboTax Federal products."
Then when you scroll down to see the various product editions, it shows the savings with that offer are:
$10 savings for Deluxe
$15 savings for Premier
$20 savings for Self-Employed Edition.
So if you used Online Deluxe, you should have been charged 29.99 for the Federal return, which is a $10 discount from the current price of 39.99.
