You don't have to spend lots of money getting your belly button pierced and then buying a navel ring. In fact, before you go the more permanent and painful route, try a fake belly button piercing first. They're inexpensive and easy to make. Maybe if you really like this one, you can get a permanent one later.
Take your fishing line or jewellery wire, and string one bead. Then fold the wire in half. This will be the dangling part of your fake belly button piercing.
Keep adding stringing beads to this fishing wire until it is as long as you want. Depending on the bead size, you may only need three beads to make your fake belly button piercing just long enough to emerge from your belly button.
Tie off the string of beads, and use glue to secure this dangling part of the belly button piecing onto your skin. These should be glued on the upper inside of your belly button.
Glue a single bead to the outside, above your belly button. Make sure it is not too high. The bead should be only a half inch or less above the upper edge of your belly button.
If you don't want to use glue on your skin, and you're not allergic to metals, you can try using industrial strength magnets to secure your fake belly button piercing. Then you simply glue the small magnets to the beads and position them on your belly button. The magnets should be no more than one-eighth in diameter to give a convincing look.