Ditto on the great idea! I've been doing this more years than I can count, mainly becus I'm such a miser. I get blinds from Wally-world for $3.95 each and can make quite a few hundred, usually cutting them up while watching a movie or something. Since I sell plants commercially you'll also find me sitting and hand-writing on them plant names/dates, etc.
One year I was lucky enough to get some blue colored ones in addition to the normal white ones. It was great because I could easily tell customers the ones with blue markers were $xx.00 and it kept me from having to price them all. Color coded! Yay!
And yep, pencil lasts much longer than most sharpie pens. If you use a sharpie (or even the "nursery markers" which also eventually fade) in your garden it helps to face the written side towards the plant so the sun won't hit it directly and fade the words.
Shoe (happily free of making markers and writing on them till next year!)
