Im new to the forums and snowboarding. But I figure I can help you with this!
I bought my first board used, and it had flow bindings on it. They are plenty tight for me (I have never used other bindings to compare it to.)
My friends all have to sit down and strap in, but I can strap in standing up or even moving down a small elevation.
Buying these bindings new would probably be expensive, but I dont see a problem with buying them used. As long as you look them over for any mechanical damage, or even cosmetic damage if that bothers you.