Hi @Jeet0, how are you? Last summer I referred my brother as a new user and we each got $25 for travel credit. My brother's reservation had to be for $75 or more. Hosts referring new hosts was $100 in travel credit when the new host has a reservation of $100 or more.
That said, Airbnb's referral rewards change.. I saw a tweet where the user referral (new guest) was reduced to $20.
If you want to know the current promotional reward amount, I suggest asking Airbnb directly...best by twitter @airbnbhelp.
I'm sure it is all credit for travel, not cash (darn!). Hope this helps!