E*Trade, the online bank and brokerage firm, wants to sell its 15,000 automated teller machines, most of which were bought just four years ago through its purchase of Card Capture Services Inc. The ATM network is thought to be worth around $100 million. The machines may retain the E*Trade brand, since they are regarded as an important distribution channel, though not a core business. One potential buyer could be Atlanta-based NetBank Inc., which owns 5,700 ATMs. E*Trade, which is based in New York, has diversified from its original brokerage operation into other businesses, including insurance and mortgages.