this one is an applique set with 12 different thought bubbles.. and yes they are free...no sign in required..
There are santa stamps: naughty, nice in the free embroidery section.
I see you have your answer Molly, so here is a *4U and everyone else. :)
Use any small circle applique, there are several in Designs by Cuties that could be used.
here's the link I think your looking for