MONO cartridge

I am about to throw a second arm on my Nottingham and am looking for suggestions regarding a MONO cartridge. I've heard several dozen stereo cartridges in the last few years but it's been a couple hundred years since I've entertained the idea of a mono pickup. I had a Shure and once that was good - a Stanton that was less so as I recall. How about today? Let's say $500 or less. Obliged. Oh, I am going to be using a RB250 on the mono side for now.
4yanx, It's my understanding that Grado will produce ANY of their wood bodied MM cartridges in mono format upon request. From what I understand the pricing is the same as the stereo versions.

Also, the Denon DL-102 is a mono high output MC that is still available.

I believe there is also a Shure model still available. I don't know the model #, but from what I remember it was more for the wider groove 78rpm record usage. The Grado and Denon both use standard stylii configuration.

Of course the Lyra is available, but I think it far exceeds your budget.

Hope this helps, Ed.
Ed, thanks. Yeah, I'm not sure I want to go too high on the mono cart at this point. Maybe the idea would be to buy a good used one from someone trustyworthy and then maybe upgrade later (which is probably inevitable)
4yanx, I probably should have mentioned that the cartridges I pointed out are all WELL below the $500.00 price point you had suggested.

The Grado's range in price from $90.00 - $400.00.
The Denon is $130.00

ie: The Grado Platinum wood bodied, mono, can be had for <$300.00.

Just food for thought. Ed.
FWIW, I learned from an Immedia rep yesterday that Lyra is about to come out with a new mono cartridge which reportedly excellent and will retail in the $700 range. It is supposed to be close to the Helikon mono for a cheaper price.