Look in your area for a shop that does ready-to-wear clothing alterations. Sometimes dry cleaners will offer those services. Altering a dress shirt to fit you better is a relatively inexpensive service and then you don’t have to worry about this anymore. As a 6’ tall woman, this is literally one of the reasons I learned to sew.

Cheap, well-made fabric is available at thrift stores in the form of linens. Curtains, tablecloths, and sheets are a great source of high-quality fabrics for cheap!

I did this. I’m starting in my final semester this fall, after going back for my degree at 38 and 8 years experience in my field. For my field, “testing out” wasn’t an actual test, it was displaying to the professor that I could show that I had done work very similar to the curriculum for that class and could speak the jargon of my field. They only let me out of a couple requirements though, and only made it so that I didn’t have to take those classes, no credit was given to me. Mostly, my experience has led to me having a serious foot up in a lot of my classes and being able to act as an unofficial TA in some of the hands on classes. And for the classes I really should have been allowed to test out of, I still generally learned enough new material to consider it worth my time and money.