I found a huge warehourse for really cheap petg or clear pvc. 1 1/4 in id is only 4$ a foot and 1/2 is only $0.52. It is a bit stronger than average petg so dont rant about how weak it is.
http://www.usplastic.com/mobile/item.aspx?itemid=25313&catid=554
http://www.usplastic.com/mobile/item.aspx?itemid=25313&catid=554