Thanks for the ideas. Kind of cracks me up that the first person that responded suggested to not even send them. Please don't encourage my slacker behaviour of the past

Yes, that would save money, but I just want family and friends to know I'm thinking of them on their day. I always think of family on their birthdays, but I've been very haphazard in the past about letting them KNOW I'm thinking of them. I have a VERY large family, so it's not practical to call them and I want something more tangible than a facebook message. If they do throw it away, that's fine...they will still know that I went to the effort of sending them my kind thoughts.
I'll look at some of the places you all suggested. I did find another idea in my online searching and ordered some cards from Current. I'm sure they'll probably be pretty thin, but they come in at about 50 cents each!