Cheap backing card for print mounts

Recently one of the competition judges mentioned that mounted images should always have a backing card to protect the image from damage. He suggested that a suitable card was available from Leaders a catering wholesaler, situated on Stockton Road Middlesbrough[Stockton Road runs parallel to Snowden Road]. The card measures 51cm by 32cm and costs £6.75 for 50 sheets, compared to about a pound for a sheet of A2 card which will only back 2 A3 prints.