lets say you place an order on Bonobos for $130
your first time referral credit is 50 off 100
so that means the balance of your first order is $80
you apply your gilt voucher of $80
bringing your balance to zero
the gilt voucher costs $40, so you're effectively getting $130 for $40
I did the very same thing when i first signed up for bonobos and used the Jungle Cents offer (which was $50 for $100 credit) in that case my first order of $150 cost me $50
not sure i'd pay full retail for their pants, but there are some good deals to be had when combining their first time buy discount along with a promo such as the one gilt is running.