I don't know about all of you, but I detest going into a greeting card store. I end up spending so much time looking for the perfect sentiments-- which I rarely find-- and yet, I also walk out with a much lighter wallet (how does that happen??)
In any case, we've started making cards around here. Simple, fun, and far more economical. I buys stock blank card and envelope sets (I go to a craft store, but I know in an overwhelming google search there are even cheaper resources online).
The biggest cost comes up front, with both the cards and an alphabet stamp set. I like the wooden ones-- I think they last longer than foam, plus, well, I just like the look much better. Get a couple of stamp pads-- choose colors with thoughts of what type of cards you'll likely be making, what seasons you'll send them, etc.
And then? The sky is the limit! I use some favorite quotes, and often (and more fun) quotes from the mouths of my babes. To date my favorites include Maxism's like "Holy Guacamole, you gotta be kidding!" and "You are so lucky because you know the world's best toilet clogger!" (obviously that one can only darken the mailboxes of a select few).
Sometimes, the kids personalize the cards with artwork. I'm collecting other cool stamps for this pirpose too. The greatest thing about making cards, however, really is the ability to make a card with a specific person in mind-- you can really say what you want, without too much (or little!) greeting card fluff behind it.