For the cost this is a great product.  I picked them up on Amazon for a little under $4 a piece.  This is my second time buying this product.  The first time I bought four and I just recently came back for another four.  I have two in the trunk of each car and two in my camping supplies and I have two that I use a couple of times a year in the garage.  The two in the garage I hung on a wire rack and coated with "scotchguard" to increase the waterproofing.  With out the scotchguard in the pouring down rain they are good for about 15 minutes of heavy rain before they start to let water seep through to your clothes.  With the scotchguard... a little over an hour.  The hole for my face was slightly to small so I cut a tiny slit with a pocket knife at the chin and it has worked great ever since.  This is a great "stop gap" type product.  It will keep you dry while you change a tire in the rain or any number of small chores while it is raining.

Here is the thing:  They are cheap and they fold up tiny.  They are great for something to use in a pinch to keep you dry.  They are not going to be great if you plan on standing in the rain all day.  For that I would spend a little more money and buy something that is a little thicker.