One year I made her a card and bought her a gift card for a pedicure at the salon.
The card was basically a black piece of folded paper and I had cut out a rose on the front of the card and put some shiny red paper behind the cut out. Maybe you could do the same thing with some stabilized or starched fabric and put on an appliqued design on the front. Then you could use fabric markers to write something on the inside (unless you went with my route and made a black card).