For $400 your best bet is probably a used American made student model saxophone. If you're patient and you know what you're looking for you can find local deals on used 60's or 70's Conn, Buescher Aristocrat, King 613, or Selmer Bundy. Also, look for a Yamaha 23. These are all decent student model saxophones. My wife started her saxophone life on a used 70's vintage King 613 and it got her all the way through high school. It blows a lot like a Zephyr with a nice free blowing core sound and decent intonation.

The key is to have it checked out by a reputable shop or another player who knows what to look for in a used saxophone. Check for past dents, resolders, filed tone holes, broken or replaced keys, etc......

The good news is that you can find a decent used saxophone for $400, but unless you're lucky, it won't happen overnight. Another piece of advice, is not to waste your time with cheap $300-$600 new horns. These are almost all junk with very poor build quality. If a dealer is trying to sell you on a new $400 saxophone I'd walk away.