Via: Craft http://blog.craftzine.com/archive/2010/09/invadersletterpressnotecards.html
Available at: Nut and Bee http://www.etsy.com/listing/60241234/mini-notes-sweet-sweet-pea ($3.50)
There's something undeniably charming about chopping the corners off a rectangle and calling it futuristic.
What message are you trying to send? Just tell the sock monkeys and they'll take care of it for you.
Available at: MimosaCards http://www.etsy.com/listing/62086462/20-percent-off-charlie-brown-tree ($15 for 10 cards