I've always had a Stott (Chris Stott) Parting tool-I think CSUSA may carry them. I got mine from the man at a demo he did some years back. Basically it's a thin piece of HSS with a nice little platic coated hand grip. All you need is a piece of thin steel. I've seen people use garage sale knives ground down for that matter.
and one like this but not the Kryo version (I don't think they sell the one I have anymore): Henry Taylor Kryo
They both work great. The most important thing with parting tools, like all turning tools is to keep them sharp. I hone my parting tools with diamond "credit cards" after grinding and can usually shave hair with my parting tools.
I prefer the thin 1/16" parting tools, ground to the Firmager pattern. The regular crown is cheaper, and then you can grind it to that pattern. It's a little tougher to grind since you can rotate it, but only takes a second. Why carbide tipped?