Glad it was a blue star. I think the gold star was the one for a son killed. Many times there were multiple stars and even multiple colors on the same banner. Don't know what it is worth. Probably not a lot as there were lots out there and I am sure everyone saved theirs. But who in your family served in WWII? Grandfather? Granduncle? Father or uncle? Whom ever was in that generation. That makes it priceless.
I don't think that these were around much in the 60-70s. Good way to get your house vandalized. But I have seen them from this last go-round. I was touched. I wonder though, since the war is officially ended, is there a time for the banners to be removed from the windows? I don't know how long they stayed up after WWII ended. Perhaps until the son returned home.