I just use brown kraft paper and some basic ribbon in a color appropriate for the occasion. I think maybe $15 in materials has given me a solid decade of gift wrapping and I haven’t even gone through half of it yet. Costs basically nothing on a per gift basis, and I get way more compliments on my wrap jobs than I did before I switched to using brown paper.
They let us use them for all my college math classes.
They really don’t help much at all if you don’t understand the math, and if you do understand, you don’t need the calculator most of the time.