I made a bog for my Venus Fly Trap yesterday. I reused a bulk food container and some river rock.
1. Fill clear outer container (e.g., bulk food container) until pot is at the same height as the outer container.
2. Place cup on pot. These typically come with the carnivorous plant and aren't recommended to remain on.
3. Fill space between pot and outer container with river rock. By keeping the cup on the pot, rocks won't spill into the delicate plant and ruin it.
4. Fill outer container with water until about 1" of the pot is submerged.