I'm looking to buy a large number of credits, but not at face value. I expect and want a quantity discount.
If you buy credits via the mobile app, discounts are available.
You can get 11,000 credits for $100 (rather than 10,000). I think there may be a similar offer when buying $500 worth but am unable to verify, at the moment as the mobile app is stalling saying it is "waiting for Google Play product list".
For the "discount", I always get my credits through the mobile app when I break down and purchase them. Otherwise, I take time each day to earn credits via the videos @ 2cr per video.
Additionally, there are times when WGT offers double or treble credits for purchases of certain items. Not that I need anything, but I will sometimes take advantage when buying gifts (Oil of Olay products) or flowers. As Mother's Day is coming soon, I would look out for any offer involving floral purchases. Flowers for mom, and extra credits to boot, is a win-win!