How does one get magazines in a store?

Is it through a vendor who comes along and posts the magazines in a display and then comes back a month later and you pay what is gone? If so how do you get in contact with them?

Yes, you're right. There are companies that will come to your store, remove the old magazines and replace them with new.

Sometimes, they even credit you for the unsold ones, however that may be more useful for newspaper sales.

Check your area for "news" providers. Good luck.