luigiwu - I don't know if you mix ink, or are filling cartridges with different inks... But if you do, I would strongly recommend getting more than one syringe.
Vermiculus is spot on- go to a pharmacy. I've purchased syringes from a few different places- one Walmart, three Wallgreens, and a local pharmacy. Never had a problem. If I only want one, they pretty much always give them to me for free, but otherwise I get charged $0.05 to $0.25 per syringe. Very cheap. I have a few with a stubby plastic "needle" for some things, but you want to use a needled one for cart cleanup (if changing colors) or filling. If you're afraid of getting stuck, you can easily use a wire cutter or even some scissors and cut off the last 5 millimeters. It's still metal, and as such could still hurt if you were extra eager to self-inflict pain, but unlike a standard syringe needle, it isn't going to slip into your flesh too easily. I've snipped a few, found it worked well, but I don't ever bother to these days. Never poked myself or anyone else to date.

The PTP Write Fill Kit is great, but in the end IMHO you don't need to spend that kind of money for a couple containers an a syringe you can get for free.
Aaron