The Dock Connector Adapters will sell for approximately $10 each or three for $29, with Apple-branded new USB cables selling for $19 each. For reference, Apple's MagSafe to MagSafe 2 Converter sells for $9.99, while international pricing for Apple's earlier iPhone Micro USB Adapter is 9 ($11) or £8 ($13).
The site reports that accessory makers are worried that Apple plans to corner the market on these adapters and cables as it did with the MagSafe connector.
One source tells them that Apple would generate $100 million for every 10 million adapters sold. The company reportedly expects to sell 10 million of them before the end of 2012. Whether Apple will ever allow third party manufacturers to produce them is still unclear.