This one uses fern leaves that my sister collected on a family walk. She pressed them between 2 heavy books for a few days before sticking one in place and adding coloured card at the bottom for a box and a gold star sticker. To finish, use clear sticky-back cellophane across the front of the card so the leafy bits don't fall off.
This one is a great way to recycle old newspaper or magazines. Simply pull out a few pages and stick them back to back (so the paper isn't so flimsy). Cut out varying sizes of triangles or trapeziums to build up a Christmas tree shape and mount them on sticky foam squares for a 3D effect.
Hope these ideas are useful! If you're wondering about where to get your hands on the plain card, I picked up a pack of 10 cards with envelopes for £2 at Wilko's. Cheap as chips! You'll be able to find some in most shops that have a craft section.
Lots of Love