From what I could tell in 5 minutes looking, it can be used for 5% off, so you would need to spend $2000 to get that free $100, unless it's trading on exchanges above $1.
Are you referring to the FAQ? I think that's just insurance in case the value of ziftrcoin is less than $1. (as if 5% would really help)
https://www.ziftrcoin.com/what-is-ziftrcoin/
"ziftrCOIN is giving away 300 million coins to help consumers become familiar with cryptocurrency. Each ziftrCOIN will have a minimum redemption value of $1 when spent within the ziftrSHOP online marketplace, where Ziftr’s innovative shopping cart technology, ziftrCART, provides a user-friendly way for consumers to conduct transactions using cryptocurrency and credit cards. Think of ziftrCOINs as your very own Ziftr coupons."
So some tiny company (that's been in business for 6 years yet nobody has heard of them) is going to give away $300 million to new users for free?
Sounds totally legit.
edit: https://www.youtube.com/watch?v=7udvVbIuOJA