My calendar took less than an hour to make and cost less than $2.50, including computer paper and colored ink. I went for a "starry night" theme. Although I don't scrapbook I do have a small collection of paper, punches, and decorative scissors that I received as gifts some years ago. The only items I had to purchase were a 22" x 28" piece of black posterboard ($.89 at my local craft store), and a sheet of EK Sticko Trees & Holly stickers ($1.39). After following the instructions to cut out and glue the calendar. I cut the posterboard to 16" x 19", and then cut out a 7 1/2" x 9 3/4" rectangle to make a frame. This leaves approximately 4 inches of poster board to decorate on each side. I punched out the stars using the sheet of white computer paper on which I had printed the calendar instructions and glued each one around the frame. And that was all! It's less than perfect, but it was fun. If you'd like to make a similar paper calendar using vintage Santa or Victorian Christmas images, try this tutorial.
There are a ton of advent calendar examples and tutorials around the blogosphere.
Here are links to some of my other favorites:
this vintage advent calendar that features historical articles about Christmas and traditional recipes. Candlegrove is an excellent website that traces the ancient origins and traditions of the winter holiday season from Thanksgiving to Epiphany; this year the countdown will take place on Twitter rather than on the website. My absolute favorite online advent calendar, written by the talented Penny Schenk and found at www.catwholaughed.com, features the adorable and inquisitive black cat named Tate. Enjoy!