Fabric valentine post cards

I am going to try to mail two fabric valentines. Both have cardboard in the center and are 5 x 7 inches. I am not sure about affixing the stamp. I will stop at the post office tomorrow am and see what they advise. I will be very curious to see how they fare after their travel through the mail system.

This first is for my son and his wife, newlyweds, very simple and classic.
...and this one is for my younger adult son, more jazzy and spontaneous. I just love crazy quilting. The hearts are sew on, free motion. I purposely made the edges kind of scrappy, it seemed to be the right kind of finish for this one.

I don't think they are reading my blog, if so, the surprise will be spoiled. We will see.