Garden markers are great for beginners as the plants don't always look like what you see on the seed packet. You can buy fancy designer markers or just write on a Paddlepop stick with a felt pen, but if you want something visually appealing with a dirt cheap DIY price consider using aluminium duct tape.
Crafting weblog Aunt Peaches shares how to make inexpensive and attractive garden markers using a bit of aluminium duct tape and a box of plastic dinner knives. Cut out a piece of aluminium tape and sandwich it around the handle of the plastic knife. Then write the plant name in reverse on the tape with a ballpoint pen -- this will press out the letters on the other side and you'll have an embossed metallic garden marker. You may want to practice writing the name backward on a piece of paper first.
Fun with Adhesive: aluminium Duct Tape Garden Markers [Aunt Peaches]