A greeting card is generally a simple document - a piece of folded paper with text or images on the front and a message inside. Although there are variations, greeting cards generally follow a typical layout. Folded on the side or the top, there's a front, an inside spread (usually only half is used), and a back having any of a variety of shapes and formats and bearing. A greeting card is an illustrated piece of card or high quality paper featuring an expression of friendship or other sentiment. Although greeting cards are usually given on special occasions such as birthdays, Christmas or other holidays, they are also sent to convey thanks or express other feelings. Greeting cards, usually packaged with an envelope, come in a variety of styles. There are both mass-produced as well as handmade versions that are distributed by hundreds of companies large and small. While typically inexpensive, more elaborate cards with die-cuts or glued-on decorations may be more expensive.