depends how big you are but you can go to
The Lacrosse Equipment Superstore and scroll to the bottom and start with a starter package (I'd recommend the warrior ones) But otherwise Id reccomend just searching lax.com and getting some cheap shoulderpads, elbow pads or guards, and a cheap head and a cheap shaft just look around
The Lacrosse Equipment Superstore and find the cheap basics, here is a complete list of what you need.
Helmet
Shoulderpads
Elbow pads or elbow guards
gloves
a head
a shaft
cup
mouthguard
cleats (optional but recommended)