Paddock Spares has 'em for $14.35 (you'll have shipping costs but can't imagine it would be that much). It's part no LR503GR.
Shipping from them is dead easy and quick, say around a week to receive.
Hope that helps...
Edit: I'm not certain this is the part you're looking for afterall. And that part number is for the galvy one- if this is the correct part, then the part no for the black one (rather than galvy) is LR503BR. I'm attaching a pic of the LH one as there's no image available for the RH one.