A:Answer You mean to use the Echo as a smart speaker to control smart devices, set reminders, create a grocery list, etc? No, you don't need to pay anything because it's a stand alone device. There -may- be a subscription charge for the devices you connect to it (Arlo cameras, for instance). However, those subscription charges are rare and you'll know about those charges when you purchase the device.
I don't know if you can use them without having an Amazon account, so you may need to sign up for one; but there's no charge.