How to ask for plant cuttings?

I know the title of this post sounds dumb, but what's the secret to asking for plant cuttings and divisions from neighbors or fellow gardeners? I love gardening, but I have a budget, and let's just say gardening is a small percentage of that budget. I rely on what I get from plant and seed swaps and cuttings, and divisions from my parents and friends. I never really asked someone for a plant cutting or division out of their yard until recently. I asked for the first time this past weekend at an estate sale (my first mistake), and I was basically told no, which I totally respect; however, it was one embarrassing because I asked while I was checking out and the lady running the estate sale was a total jerk about it and said at the end if only I could afford the million dollar home I could have all the lilies I wanted in front of everyone. Secondly, it was sort of discouraging in a way, as it was my first time, and I'm sure it won't be my last.