To make these, I sketched the cards out by hand and used Photohop to map out the placement of the sentiments and the fonts. After that, I used the Silhouette Cameo (and the program that comes with it) to cut out the letters.
I'm half tempted to sell these or others like them, but the pop-ups just take so darn long to put together that I'm reviewing the situation. The letters were teeny! I think I better think it out again.
[Can you spot the reference to Oliver! (1968) which I got to watch last weekend? Yay for long weekends.]