it depends. some people explicitly state that they don't want you to use their tutorial to make something to sell. It might be worth it to drop them a line just to let them know you are making things for a local craft fair (not online selling). It also may be nice to note on the tag that the design was inspired by some one else.
I've researched this some and from what I understand a piece of ribbon folded into a loop and sewn in between to pieces of fabric is a copy right infringement. So tags sewn on to balls, blocks, dolls, any ribbon looped over and sewn between to pieces of fabric. And yes it's stupid. And yes there are other companies that make them. Any yes Taggie corporation does police etsy and get's you into trouble with your etsy account even if you have just ONE posted on your site.