I am mailing a small 2.5" x 2" box. It only weighs 1 maybe 2 oz. The USPS calculator says the price is the same for either weight... $1.71. Can I put 4 forever stamps on it to avoid the post office? I don't care if its over paying, I just want to save time if possible. I tried calling USPS just to find out that they are closed today. (didn't think about it being a holiday) I'd still like to drop it off today because I will already be out. Thanks!