I just looked and found the following disclaimers:

2. Must purchase a new 2-year plan with a select wireless provider to qualify. Subject to carrier credit approval. While supplies last.

3. After discount and mail-in rebate from AT&T with a new 2-year account and subject to carrier credit approval. While supplies last.

Been shopping for one recently so I can say the offer on E-Trade is not particularly more enticing than what AT&T offers on their site...