If you have AppleCare+ coverage, you will pay only the "deductible"; check the terms for your plan. In most cases it's US $79. If you do not have AppleCare+ on your iPhone, Apple now will replace screens on the iPhone 5C, at least in the US, for US $149. Availabllity of repair services may vary by country and by Apple Store, so call Apple Support or visit an Apple Store and ask for information. If Apple will not offer screen replacement service at an Apple Store in your area, they will replace the entire iPhone. See:
http://www.apple.com/support/iphone/service/faq/
There are independent iPhone repair services that may be able to do the repair for less than Apple's out-of-warranty charge. Do a web search for "iPhone repair". Note, though, that if you elect to have the iPhone serviced by an unauthorized shop, all further warranty and support from Apple will be voided.
Regards.
Forum Tip: Since you're new here, you've probably not discovered the Search feature available on every Communities page, but next time, it might save you time (and everyone else from having to answer the same question multiple times) if you search a couple of ways for a topic, both in the relevant forums and in the Apple Knowledge Base, before you post a question.