Sharonm, I don't think the person who you spoke to about this is not all that superior at all, sounds more like an idiot to me.
My suggestion would be to go to another frame shop and ask them to sell you ten dollars worth of scrap mats, after you explain why you want them, they will probably throw in a few extra or even comp. you the whole pile.
Your approach is exactly how most of us learned, we bought a book, then practiced on scraps.
Learn this skill and as many more as you can, then tell your idiot, er "superior" to shove it, then open your own shop. The one thing you are learning from that person is how NOT to motivate employees.
John