2 bundles available:
United By Blue
Each bundle costs $35 and gets you a code worth $50 (not applicable for shipping costs) at each store.
These are all "overpriced" hipster/yuppy stores and most of their items are at a price point well beyond $50, but if you grind a little bit you can find some good deals.
I don't think you can stack another code at any of these stores with the gift card, but if I'm wrong someone feel free to correct me. They should work on sale items though.