My 15 year old son is perfecting his golf game and has found this to be a most useful training tool for practicing at home.
Great Indoor Practice Rug
This indoor putting "rug" would not necessarily replace some of the more higher priced putting green models, but will do in a pinch at least help with putting alignment. Its just too far from the feel of a real green, but its inexpensive and very portable, as it easily rolls up. My kid whose just getting into golf really likes it though, so I suppose for those budding Michelle Wie-s this will work.