The flower in the sample has been enhanced using a faux flower and a brad. Both of these items were originally intended to be scrapbooking supplies.
If you scrapbook, take a look through your scrapping supplies to see if you already have a suitable flower and brad to use for your necklace. Even if you do not scrapbook, you might already own some baubles and trinkets that you could use to dress up your flower. I encourage you to take a look through your crafts supply stash. Perhaps you own a fancy button or some jewelry findings that you could use.
If you don't mind doing a bit more work, you could also use one of the flowers from a stem of silk flowers. Rebecca Ludens has written a tutorial for re-purposing silk flowers. Her article was written for scrapbookers, but crocheters can use this technique too.
Keep in mind that Rebecca used large flowers in her tutorial, but you would need to use smaller flowers. In the pink and black version of my crocheted necklace, the faux flower I used is from a stem of hydrangea flowers. Hydrangeas are a more appropriate size than large daisies are for this particular project. If you plan to make a whole bunch of these necklaces as gifts, Rebecca's method would be worthwhile; you could buy one stem of hydrangeas, and it would give you many suitable flowers to use.