I am trying to locate a chain ring guard for my bike.

I have one for my mountain bike and it is a simple plastic ring thing that works like a charm, keeping oil off my pants and my pants from getting caught up in the ring as I pedal.

New bikes, even low end ones seem to all have them, but there is no after-market ones except for the uber-expensive carved from a single piece of metal ones.

Any suggestions or links?

To me, this is a simple thing that you should be able to get at the dollar store.

I am making one out of 1/8 plywood now but it would be nice to just be able to buy one.