Here are the official prices for unlocked, contract-free iPhone 5C and 5S from store.apple.com. Price may still be different when it eventually becomes available here in the Philippines.
Note that the price difference between a 5S and a 5C is only $100 (roughly P4300) so unless you really want a colored plastic phone, you are better off getting a 5S.
These phones will be available on September 20th in the US. If you plan to get it ahead of everyone else, you may try out Amazon.com and purchase it using GCASH American Express® Virtual Pay. Just click here to learn more about using GCASH in making a purchase abroad.
You may also wait for your preferred telecom provider (GLOBE) to have the phone available and subscribe to a plan.