I bought my Vibe used, so the first owner paid for the carpet cargo mat and floormats. I often use the floor of the back seat for groceries, if I have only a few items.The cargo carpet mat helps keep heavy cargo from sliding, like 50# salt blocks, but not the groceries, as you mentioned. Almost immediately, I went to a nearby Dollar Store and purchased 3 small plastic 'milk-carton-type' carriers, and a set of velcro ties to link them together. Total investment $4.00 (3.00 for 3 cartons and $1.00 for the velcro ties). I probably would've purchased more that day, but they only had three matching (red) ones. These will each hold a plastic gallon of milk or juice and keep it from sliding on the carpeted cargo mat surface.(Larger 'milk-carton-type' carriers are also available, of course.)When I don't need them, I just put them in the garage. Later I purchased the (Toyota) cargo net set on eBay for about 1/2 what GM wants (I paid around US$30 including shipping.) I leave the large cargo net across the back, and the 3-milk-type carriers to one side. I've NEVER used the small side cargo net that was part of the set. These containers hold all the requisite junk much better, and don't slide on the carpet side of the rear cargo mat.I also have a 6'x8' gray plastic tarp that I use when I transport my lawnmower. (shown folded up in it's original packaging). More info about it here:
http://forums.genvibe.com/zerothread?id=9707Someone also mentioned that the cargo carpet is pretty useful when turned carpet-side-down, especially for wet or dirty cargo. With cargo net in place With cargo net down Detail of velcro tie