Google Voice!

Google Voice gives you a free phone number for calling, text messaging, and voicemail. It works on smartphones and computers, and syncs across your devices so you can use the app while on the go or at home. Keep in mind: Google Voice is currently only available in the US All calls made using Google Voice for iPhone use the standard minutes from your cell phone plan Calls are placed through a US-based Google Voice access number, which may incur costs (e.g. when traveling internationally)