That error does not seem to me to be an issue that is related to whether you do or don’t have a paid developer account.
Try cleaning the project (Shift + Command + K) and then try to build it again (Command + B)
If you have created a Developer account, but it is not paid, then there are restrictions on the number of Apps you can create in a 10 day window and there are restrictions on how many Apps you can install on a real device.
A paid account means that you can create as many apps as you like and put those Apps on your real device. Although I think that there are restrictions on the total number of authorised devices you can connected to your Mac but I don’t recall what that number is.