My family is full of people who are allergic to metal. I am one of them, I work with metal, but I am allergic to most kinds. Nickel, iron, steel, platinum and a few more. There are ways to get around metal allergies and jewelry without buying plastic and high quality expensive metal.
Step 1: The Way Around Allergy
I was told I couldn't wear my steel ring and it was my favorite (I was 10) and I hated it so much. I was told I could get a plastic painted metal ring or I could get a gold plated ring. I didn't like either of these as I was a stubborn kid :). We looked online and founded some pad to put in between me and the metal and it looked funny, then I hit me. I could coat my jewelry in the nail polish clear coat so I shouldn't touch the metal, but it would still be a real metal ring.
Step 2: Application
Just brush on a normal coating 2-3 times and it should last months. It will be a barrier between you and the metal. It makes lower quality metals like nickel wearable to people who are allergic. I hope this helps to make jewelry wearable again.