Prior to making a purchase of that belly button ring that you have always coveted, try and give it a second thought just to save you any troubles. Avoid any metals that your body is allergic to. The most preferable options are bioplast, titanium, stainless steel and gold. It is said that for your fist time to wear the ring you should use the bioplast one due to its biocompatibility. And the wound will be less likely to swell or pick up an infection. They are also the best alternative if your body reacts with metal of any sort.
Stainless steel navel rings are another option since they are mixed with other materials to make them resistant to rust and corrosion. Notably it is vastly used to make shafts then the balls and dangles are made from different material.
Then the other option is to use titanium made rings which are very light as compared to their stainless steel counter parts. This metal is pure unlike stainless steel and contains no impurities and is therefore an alternative for those who are allergic to steel. This metal appears in different colors and you should be aware that some of the black ones are actually stainless steel that is coated with titanium.
You can also settle on the classy golden belly rings. They are very stylish, durable and are safe on your body. Do not look too much at the price but rather on the value you will have gotten for your money.