Cost of Replacement Retainers

Hi all,

I got my braces off a long time (7+ years) ago and I have been faithfully wearing my retainer since then, but over time it has gotten a bit of calcium buildup and is honestly a little gross. I was thinking of buying a new one, just to have it be fresh, but does anyone know how much it would cost? I know that a replacement retainer is usually around $200, but would it be less if I already had the original retainer and just wanted to make a copy of it? I would think it would be less expensive since there is no need to make molds of my mouth.