Sometimes it's tricky to find pretty stationery to write to your pen pals on, but these quick and easy ideas should have you sorted. Always use nice medium thickness art paper when using paint, to prevent the paper from warping. I usually buy a pad of art paper and tear off individual pages as needed. If you can't get hold of anything thick, simply keep your finished design under a heavy book for a day or so, which will help it sit and flat.
Idea 1: Paper doily + ink spray :: Position a couple of paper doilies over a piece of paper and spray. If you don't have any ink spray, you can make your own with 1 part paint & 2 parts water, then pop it in a spray bottle.
Idea 2: Washi tape :: Tear off small pieces of washi tape and stick around the outer edge of the paper.
Idea 3: Paint + hole punch :: Punch a series of holes in a piece of paper, secure it on top of a second sheet of paper (hold with two paperclips) and paint over the top of the holes. Remove the top sheet and let the base dry - you can then add a second or third colour using the same method.
Idea 4: Watercolour paints :: Use a paintbrush to paint the surface of your paper - leave a small gap of paper around the outer edge.
Idea 5: Fabric + stapler :: Cut small strips of fabric and staple them to the top and bottom of the paper.
Idea 6: Embroidery cotton + needle :: Blanket stitch around the outer edge of the paper.
Have fun & happy writing,