When you have a baby you need a lot of baby blankets.  It can be expensive to buy the blankets in stores, and the are often too small to swaddle a baby in after the first few months.  There is a pratical solution.

Go to the fabric store and get 1 and 1/2 yards of flannel.  You only need this much because you are going to hem the edges on a sewing maching.  The flannel will keep the baby warm so you don't need to have two layers or batting. 

Making the hem is easy.  All you need to do is iron in a 1/4 inch seam all the way around the fabric.  Then fold that over and iron in a 1/2 seam.  This will make a very nice edge on the back side of the fabric.  Go around the hem with a sewing machine on a straight stitich and toss it in the wash before the first use.  You are all done and have a nice sized baby blanket that is perfect for swaddling baby in less than 30 minutes and it costs less than five bucks.