The guy I bought from on ebay doesn't list any for sale currently. He was repachaging into syringes and I think I got mine for around US$10 a couple of years ago; I'm still using it.
Be careful, because there's some confusion among some sellers (seems to be a translation problem, maybe) about the difference between "paste flux" and "solder paste". Paste flux is just that, flux in a paste form (as opposed to liquid) - there's no solder in it. Solder paste is solder with the flux mixed in.
I got some paste flux from deal extreme. It worked, but was a bit stiff, and not easy to dispense.
If it doesn't come in a syringe, get yourself some syringes and some dispensing tips. I bought something like this
so I had room to experiment. You want dispensing tips, not needles - needles are sharpened, dispensing tips are not.