So are thousands of junkies. Have ya tried going to the various medical supply companies? You can simply grind down the points. If you need to see fluid (going in or out) you'll need to contact a prop house like I.S.S. (Independent Studio Services) (818) 951-5600. That is, of course, if you live in Southern California. They're in Sunland. You rent a kit that has various versions of the syringe. A practical one, one with a retractable needle for dispersing fluid (blood or injectables), etc. They have kits from most time periods.

Here's the way you can do it for cheap. Buy real needles and grind the points off. You shoot a real needle going toward the vein. Cut to the person's reaction, then (having swapped out the needle for a dull one) see it "in the vein." All the while it's really just a metal needle without a point ON the vein. Do it in close up. To buy a needle rig will run you hundreds of dollars. However, if you make contact with a prop house and send them a rental check and a replacement check, I'm sure they'll rent the rig to you and ship it. When you return the rig, they'll return the replacement check. Simple. The only other way I see it done is to rent a human arm with an FX bladder under the skin so you can draw the blood and stick it in in the same shot. Hope this helps.

I'm here to help. Don't forget to get a rubber tourniquet - in case you need another cut away type of insert. Please let me know how it turned out for you.