They would be very simple to make. Cheep too. All you need is handle webbing, like you would see on a gym bag, and some velcro. I would get about 1 1/2 yds webbing and then you can cut it to the right size. The velcro would go on the bottom as a safety feature and you can even get self stick if you don't sew. If you want to hem the bottom so it doesn't fray you can get steam a seam which is a fusible webbing or use a good fabric glue. If you don't want to hem it but want to stop the fraying get a product called fray check to put on the ends.
Webbing comes in both cotton and polyester and usually in a few colors. I recomend the cotton just because of comfort. It only costs about $1/ yd. If you want to put a clip on the bottom you can look in the notions area of your fabric store and find something appropriate.
Good luck!