Hi, this has been covered before, the rearguards does an excellent job, but is pricey for a bit of plastic. I have one on mine and wouldn't be without it, has protected the bumper from numerous knocks and scratches, and the dog jumping in and out, still not marked, a quick wipe with back to black and its like new. After i bought mine I did find a possible alternative, very much cheaper but probably not so robust.
E-TECH CAR DOOR SILL & LOWER BODYWORK PROTECTOR / TRIM GUARD -£10 inc post, on ebay, It can be used anywhere, including door and boot steps to prevent damage from people, pets and loading luggage in and out of your car.
E-Tech Sill Guard is a specially developed, heavy duty rubber tape that has a weather proof adhesive backing. Supplied on a 9cm x 2.36m roll, it can be cut to shape and length to fit any car or application.
http://www.ebay.co.uk/itm/Black-Car-Door...3f1f7d667c
You pays your money and takes your chance. I didn't find this until after I bought my rearguard.