Miniscule. Best case, you end up paying $33 in taxes to get $100 gift cards to all kinds of retailers. Buddy passes are not worth the taxes, in my opinion. Comes out to about $15 per buddy pass. The merchandise is not worth the taxes, either. Sign up and stick with the gift cards. Hope that helps.
Oh, and don't come to work sick for a month's swag. Not worth it.