Use what you can afford. If you are a beginner, don't get wrapped up in what you "must" have.
Excellent thread and quilt shop quality fabric is great for making heirloom quilts. It should be used by anyone who can afford to use it and deems it worthwhile.
Cheaper thread and lower quality fabric is great for making quilts, too. If that's what you can afford, and you enjoy quilting don't let the fact you don't have top quality materials prevent you from giving quilting a try.
I use what I can afford because I enjoy the process. My quilts may not last 100 years. I won't either.