I don't know where you can get it, but I would caution you to be careful using it mark casino chips.

I know that on the Ebay boards many people recommend using these markers, so that you can catch people switching goods and returning them to you.

The problem with marking collectibles like casino chips is that most of us would view you writing on them as damaging them, and many collectors use blacklights to examine their chips so it will be noticed.