I get mine from my local farm supply store. They are USP grade, and super cheap! I have one 3ml, 5 10ml, and 2 60ml syringes with needles of various gauges, and I think(didnt get them all at the same time, but i think the most expensive were the 60's at $1.75/ea)I paid less than $15 for all.
I use syringes often to inject marinade into meat, and they were the cheapest place to get them. The grocery store wants something like $10-15 for the same 60ml syringe I paid $1.75 for just cuz is was packaged for injecting meats...