Vector has 22 kits for $250. They rarely come up for sale used. Several people report that they needed to tweek the mags to get them to run smoothly. Also, Vector will tune your kit and mags to your uzi.
I just put together a 45ACP kit for my FA Vector. Bolt, lower and barrel cost me over $600 and the best deal on GG mags was $16 each for like new. Vector is supposed to have some converted 9MM bolts within the next month or two. I bought an IMI bolt. They had a few units at SAR. I had to file the backs of my GG mags to get the mags to seat properly.