Knitting my own bag????

I was looking online and found these neat project bags. They were $20 and under depending on who made them. Then I got to thinking that I could make my own! I have a bunch of yarn that I don't want and I could use this to make my bag. The picture is from this pattern: http://chrisknit.blogspot.com/2008/05/simple-color-patterned-pouch.html. I don't want to make anything fancy but it also might be a way to learn stranded knitting-using more than 1 color. I was thinking stripes, maybe 1-3 rows of the other color every 5-10 rows. Will have to do research on stranded knitting before I start. I decided to use one strand of green and one strand of white and knit with both together. That way I use up some of both yarns. I figure, the only thing I would have to buy would be circular needles. I want them anyway....