AMD|A64 3800+ 939 512K R Thermal Compound

Hello, Im planning on throwing some old computer parts I have laying around to build a computer, i am going to use the AMD|A64 3800+ 939 512K processor, i dont plan on overclocking, but i might a little

I have the standard AMD heatsink and fan, but no thermal compound what should i get ?
what is the cheapest i can get and it still be usefull

Toothpaste, you'd be amazed.

It might not be as good as MX-2 or AS5, but it will work in a pinch. Dunno where the test is, kinda old test, but yes it works. I'd never use it.