Just bring what your willing to pay, and when it comes down to it, just be like; "Hey, all I got is $275, are you willing to accept this today?". That's how I got mine. But $400 does seem pretty steep. Especially without tires and you don't know what brand they are. But who am I to say which rims are cheap quality or not. I just ask my friends lol. Good luck!
For a little more than $400 you could get some new XXR's and better sizing. I don't care what anybody says.. they're pretty decent wheels for the monayyy.