Get 20 Flat or Folded 4×8 or 5×7 Holiday Card from Vista Print for $1.99 + shipping.
You can either choose to customize your cards with photo (or photos) or pick simple designs and customize you message.
While I doubt this will cover ALL you Holiday card needs – it should be enough to send special cards to immediate family.
(Or customize and make them thank you cards from your kiddos for all their Holiday Loot.)