Many people just design them using their favorite drawing program, then print them out on cardstock.
We print ours out on Avery Label paper #8255 (one-sheet label paper). Then we peel off the back,
affix the label to construction paper,
cut out the cards and
have them laminated at the local copy shop.
Don't have laminate each one individually; lay them out in the laminate sheet with some space between them. After
the lamination is done, you can cut each card out of the finished lamination sheet.