Apple has started taking pre-orders for iPhone 5C in US and in other countries including Australia, Canada, China, France, Germany, Hong Kong, Japan, Singapore and the U.K. You can order directly from the Apple online store or through carrier sites.
The iPhone 5c is selling for $99 (16GB), $199 (32GB) with two year contract from Sprint, AT&T and Verizon. You can also order the phone directly from the carrier websites if you prefer. If you are looking for an unlocked version of the device it is available from T-Mobile for $549 (16GB) and $649 (32GB) model.
You can also order from carriers in other countries as well as Apple stores depending on the region. Apple released iPhone 5C along with iPhone 5S this week. The pre-orders will be delivered from September 20th onwards. iPhone 5S will also hit the stores on that day.