Coroplast supplier NYC

Good day to all,

I work for a private collection located in the NY Metro area. I have found that corrugated plastic (brand name Coroplast) is a material I am using with increasing frequency.
I am transitioning from less desirable materials to Coroplast for storage, and my supplier has bumped their prices from 13 dollars for a 4 x 8 sheet to 19 dollars.
Might someone in the NY Metro area be willing to share their supplier for this material? I am having difficulty sourcing the material.
Your help would be much appreciated.
Please feel free to contact me off list at: amesregistrar@gmail.com

With thanks,
Martin

harborsales.net
They're based out of MD. I know their delivery area includes at least NE Pennsylvania, but I'm not sure about NY. You have to have an account to see pricing, but 4mm coroplast is $13.

If you haven't already I would check with distributors who serve the sign making profession (big time users of the stuff). Things don't exactly come cheap in the Bay area but I have been buying std. white 4mm Coroplast for $9.97 a sheet here.