I used blank 4x6 cards which were about 1.46 for the entire pack which we used 30 of. We got the pencils and the heart mazes from the dollar store, although I've seen them online even cheaper still. But I'm not always known for patience.
(I apologize for the poor picture - 3, 4 & 6 year old children do not want to wait for mom to take weird pictures of their stuff)
Even though they weren't cut perfectly, they still got the job done...
I let her tape the pencils on. (I should warn, this ended up costing me a nearly entire roll of tape!) When I designed the cards I intended to have them all taped on the side where there is a little extra room, but half way through she decided she wanted some variety. So she taped them on any of the sides.
So for less than 5 dollars (more if you count the tape), and about 35 minutes give or take, we have nearly 60 home made valentines! And she loved the play on the words!