How do I sync music without a subscription on iPhone?

Tried to sync my phone but apple is now saying that I must have a subscription service in order to sync. This seems outrageous since I have already paid for these songs and would like to transfer them to my phone. Does anybody know if thee is a work around? Seems illegal to me to force you to pay for a subscription that you do not want or need just to be able to sync music you already paid for, to your phone,

[Re-Titled by Moderator]

Original Title: Syncing phone