I bought an Armstrong 104 used from Steve Sklar for about $120, it was actually $85 plus a mouthpiece trade. It has absolutely served me well, decent tone, intonation, and it doesn't hurt that I practice a lot! (meaning...any "name brand" student flute and hours of practice and you'll be ready to go).
Actually, with your budget I would suggest a Yamaha student flute. I couldn't afford one when i was flute buying (they are a little more than $300 used i think) but two saxophone teachers I had who were gigging pros in NYC both used Yamaha student flutes professionally and had all the flute they needed.