I used to buy referrals here on bitcointalk all the time. For a while I was getting $20 per referral, then I would get $15 off a ride, and now I am receiving $10 off a ride. (I'm in the US).

In the app, it states that I would get up to $10 a ride if I referred under "Free Rides".

Using your service, would I still get $15 per free ride? Or $10?

Also, I know the free ride credits expire... what about your $10 Uber credits that you are offering for $4. Do they expire?

Another question.. in your $18 example, the first $15 was the "free ride" so the customer has to pay $3. Can that $3 also be paid with the $10 Uber credit you can provide? Can you use both in one ride?

Thanks in advance for your answers. I asked them here instead of privately as I'm sure others will benefit from knowing.