I've been using DVDPlay for a few months. I go to the Vons in Pasadena, usually on Colorado and Sierra Madre. They seem to have a pretty good stock.
Apparently they have taken down all the promo codes from the kiosk and none of the ones that I recently received worked, so I decided to do a search online and found a few links and codes which I will try next time.
http://www.dvdplay.com/dvd-rental-machine/kiosk-promocodes.html - I don't see any promo codes currently listed.
Other promo codes:
PromoCode "PLAY" for a FREE rental.
PromoCode “MISSU50” for a 50¢ rental
You can also get DVDPlay promo codes for free and discounted rentals from InsideDVDPlay [ http://www.insidedvdplay.com/ ].
Also, if you happen to have a Redbox (same idea as DVDPlay) nearby, you can get codes from InsideRedbox [ http://www.insideredbox.com/ ].
One of the things I don't like about the service is having to return the rentals by 7pm the next day, if they are not returned at 7pm you get charged the full price rental. So last week we rented two movies. I had a promo code, so two movies came out to $1.60, we did not return by 7pm and my credit card was charged twice for $1.07. Perhaps DVDPlay can offer another day for $.50 extra, or some way to not have to pay the full rental price, or at least offer a grace period of an hour. I don't know how they came up with 7pm.